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LeetCode

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Solutions

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#	Solution	Tags	Difficulty	Remark
0001	Two Sum	Array,Hash Table	Easy
0002	Add Two Numbers	Recursion,Linked List,Math	Medium
0003	Longest Substring Without Repeating Characters	Hash Table,Two Pointers,String,Sliding Window	Medium
0004	Median of Two Sorted Arrays	Array,Binary Search,Divide and Conquer	Hard
0005	Longest Palindromic Substring	String,Dynamic Programming	Medium
0006	ZigZag Conversion	String	Medium
0007	Reverse Integer	Math	Easy
0008	String to Integer (atoi)	Math,String	Medium
0009	Palindrome Number	Math	Easy
0010	Regular Expression Matching	String,Dynamic Programming,Backtracking	Hard
0011	Container With Most Water	Array,Two Pointers	Medium
0012	Integer to Roman	Math,String	Medium
0013	Roman to Integer	Math,String	Easy
0014	Longest Common Prefix	String	Easy
0015	3Sum	Array,Two Pointers	Medium
0016	3Sum Closest	Array,Two Pointers	Medium
0017	Letter Combinations of a Phone Number	Depth-first Search,Recursion,String,Backtracking	Medium
0018	4Sum	Array,Hash Table,Two Pointers	Medium
0019	Remove Nth Node From End of List	Linked List,Two Pointers	Medium
0020	Valid Parentheses	Stack,String	Easy
0021	Merge Two Sorted Lists	Recursion,Linked List	Easy
0022	Generate Parentheses	String,Backtracking	Medium
0023	Merge k Sorted Lists	Heap,Linked List,Divide and Conquer	Hard
0024	Swap Nodes in Pairs	Recursion,Linked List	Medium
0025	Reverse Nodes in k-Group	Linked List	Hard
0026	Remove Duplicates from Sorted Array	Array,Two Pointers	Easy
0027	Remove Element	Array,Two Pointers	Easy
0028	Implement strStr()	Two Pointers,String	Easy
0029	Divide Two Integers	Math,Binary Search	Medium
0030	Substring with Concatenation of All Words	Hash Table,Two Pointers,String	Hard
0031	Next Permutation	Array	Medium
0032	Longest Valid Parentheses	String,Dynamic Programming	Hard
0033	Search in Rotated Sorted Array	Array,Binary Search	Medium
0034	Find First and Last Position of Element in Sorted Array	Array,Binary Search	Medium
0035	Search Insert Position	Array,Binary Search	Easy
0036	Valid Sudoku	Hash Table	Medium
0037	Sudoku Solver	Hash Table,Backtracking	Hard
0038	Count and Say	String	Medium
0039	Combination Sum	Array,Backtracking	Medium
0040	Combination Sum II	Array,Backtracking	Medium
0041	First Missing Positive	Array	Hard
0042	Trapping Rain Water	Stack,Array,Two Pointers,Dynamic Programming	Hard
0043	Multiply Strings	Math,String	Medium
0044	Wildcard Matching	Greedy,String,Dynamic Programming,Backtracking	Hard
0045	Jump Game II	Greedy,Array	Medium
0046	Permutations	Backtracking	Medium
0047	Permutations II	Backtracking	Medium
0048	Rotate Image	Array	Medium
0049	Group Anagrams	Hash Table,String	Medium
0050	Pow(x, n)	Math,Binary Search	Medium
0051	N-Queens	Backtracking	Hard
0052	N-Queens II	Backtracking	Hard
0053	Maximum Subarray	Array,Divide and Conquer,Dynamic Programming	Easy
0054	Spiral Matrix	Array	Medium
0055	Jump Game	Greedy,Array	Medium
0056	Merge Intervals	Sort,Array	Medium
0057	Insert Interval	Sort,Array	Medium
0058	Length of Last Word	String	Easy
0059	Spiral Matrix II	Array	Medium
0060	Permutation Sequence	Math,Backtracking	Hard
0061	Rotate List	Linked List,Two Pointers	Medium
0062	Unique Paths	Array,Dynamic Programming	Medium
0063	Unique Paths II	Array,Dynamic Programming	Medium
0064	Minimum Path Sum	Array,Dynamic Programming	Medium
0065	Valid Number	Math,String	Hard
0066	Plus One	Array	Easy
0067	Add Binary	Math,String	Easy
0068	Text Justification	String	Hard
0069	Sqrt(x)	Math,Binary Search	Easy
0070	Climbing Stairs	Dynamic Programming	Easy
0071	Simplify Path	Stack,String	Medium
0072	Edit Distance	String,Dynamic Programming	Hard
0073	Set Matrix Zeroes	Array	Medium
0074	Search a 2D Matrix	Array,Binary Search	Medium
0075	Sort Colors	Sort,Array,Two Pointers	Medium
0076	Minimum Window Substring	Hash Table,Two Pointers,String,Sliding Window	Hard
0077	Combinations	Backtracking	Medium
0078	Subsets	Bit Manipulation,Array,Backtracking	Medium
0079	Word Search	Array,Backtracking	Medium
0080	Remove Duplicates from Sorted Array II	Array,Two Pointers	Medium
0081	Search in Rotated Sorted Array II	Array,Binary Search	Medium
0082	Remove Duplicates from Sorted List II	Linked List	Medium
0083	Remove Duplicates from Sorted List	Linked List	Easy
0084	Largest Rectangle in Histogram	Stack,Array	Hard
0085	Maximal Rectangle	Stack,Array,Hash Table,Dynamic Programming	Hard
0086	Partition List	Linked List,Two Pointers	Medium
0087	Scramble String	String,Dynamic Programming	Hard
0088	Merge Sorted Array	Array,Two Pointers	Easy
0089	Gray Code	Backtracking	Medium
0090	Subsets II	Array,Backtracking	Medium
0091	Decode Ways	String,Dynamic Programming	Medium
0092	Reverse Linked List II	Linked List	Medium
0093	Restore IP Addresses	String,Backtracking	Medium
0094	Binary Tree Inorder Traversal	Stack,Tree,Hash Table	Easy
0095	Unique Binary Search Trees II	Tree,Dynamic Programming	Medium
0096	Unique Binary Search Trees	Tree,Dynamic Programming	Medium
0097	Interleaving String	String,Dynamic Programming	Medium
0098	Validate Binary Search Tree	Tree,Depth-first Search,Recursion	Medium
0099	Recover Binary Search Tree	Tree,Depth-first Search	Hard
0100	Same Tree	Tree,Depth-first Search	Easy
0101	Symmetric Tree	Tree,Depth-first Search,Breadth-first Search	Easy
0102	Binary Tree Level Order Traversal	Tree,Breadth-first Search	Medium
0103	Binary Tree Zigzag Level Order Traversal	Stack,Tree,Breadth-first Search	Medium
0104	Maximum Depth of Binary Tree	Tree,Depth-first Search,Recursion	Easy
0105	Construct Binary Tree from Preorder and Inorder Traversal	Tree,Depth-first Search,Array	Medium
0106	Construct Binary Tree from Inorder and Postorder Traversal	Tree,Depth-first Search,Array	Medium
0107	Binary Tree Level Order Traversal II	Tree,Breadth-first Search	Medium
0108	Convert Sorted Array to Binary Search Tree	Tree,Depth-first Search	Easy
0109	Convert Sorted List to Binary Search Tree	Depth-first Search,Linked List	Medium
0110	Balanced Binary Tree	Tree,Depth-first Search,Recursion	Easy
0111	Minimum Depth of Binary Tree	Tree,Depth-first Search,Breadth-first Search	Easy
0112	Path Sum	Tree,Depth-first Search	Easy
0113	Path Sum II	Tree,Depth-first Search	Medium
0114	Flatten Binary Tree to Linked List	Tree,Depth-first Search	Medium
0115	Distinct Subsequences	String,Dynamic Programming	Hard
0116	Populating Next Right Pointers in Each Node	Tree,Depth-first Search,Breadth-first Search	Medium
0117	Populating Next Right Pointers in Each Node II	Tree,Depth-first Search	Medium
0118	Pascal's Triangle	Array	Easy
0119	Pascal's Triangle II	Array	Easy
0120	Triangle	Array,Dynamic Programming	Medium
0121	Best Time to Buy and Sell Stock	Array,Dynamic Programming	Easy
0122	Best Time to Buy and Sell Stock II	Greedy,Array	Easy
0123	Best Time to Buy and Sell Stock III	Array,Dynamic Programming	Hard
0124	Binary Tree Maximum Path Sum	Tree,Depth-first Search,Recursion	Hard
0125	Valid Palindrome	Two Pointers,String	Easy
0126	Word Ladder II	Breadth-first Search,Array,String,Backtracking	Hard
0127	Word Ladder	Breadth-first Search	Hard
0128	Longest Consecutive Sequence	Union Find,Array	Medium
0129	Sum Root to Leaf Numbers	Tree,Depth-first Search	Medium
0130	Surrounded Regions	Depth-first Search,Breadth-first Search,Union Find	Medium
0131	Palindrome Partitioning	Depth-first Search,Dynamic Programming,Backtracking	Medium
0132	Palindrome Partitioning II	Dynamic Programming	Hard
0133	Clone Graph	Depth-first Search,Breadth-first Search,Graph	Medium
0134	Gas Station	Greedy	Medium
0135	Candy	Greedy	Hard
0136	Single Number	Bit Manipulation,Hash Table	Easy
0137	Single Number II	Bit Manipulation	Medium
0138	Copy List with Random Pointer	Hash Table,Linked List	Medium
0139	Word Break	Dynamic Programming	Medium
0140	Word Break II	Dynamic Programming,Backtracking	Hard
0141	Linked List Cycle	Linked List,Two Pointers	Easy
0142	Linked List Cycle II	Linked List,Two Pointers	Medium
0143	Reorder List	Linked List	Medium
0144	Binary Tree Preorder Traversal	Stack,Tree	Easy
0145	Binary Tree Postorder Traversal	Stack,Tree	Easy
0146	LRU Cache	Design	Medium
0147	Insertion Sort List	Sort,Linked List	Medium
0148	Sort List	Sort,Linked List	Medium
0149	Max Points on a Line	Hash Table,Math	Hard
0150	Evaluate Reverse Polish Notation	Stack	Medium
0151	Reverse Words in a String	String	Medium
0152	Maximum Product Subarray	Array,Dynamic Programming	Medium
0153	Find Minimum in Rotated Sorted Array	Array,Binary Search	Medium
0154	Find Minimum in Rotated Sorted Array II	Array,Binary Search	Hard
0155	Min Stack	Stack,Design	Easy
0156	Binary Tree Upside Down	Tree	Medium	🔒
0157	Read N Characters Given Read4	String	Easy	🔒
0158	Read N Characters Given Read4 II - Call multiple times	String	Hard	🔒
0159	Longest Substring with At Most Two Distinct Characters	Hash Table,Two Pointers,String,Sliding Window	Medium	🔒
0160	Intersection of Two Linked Lists	Linked List	Easy
0161	One Edit Distance	String	Medium	🔒
0162	Find Peak Element	Array,Binary Search	Medium
0163	Missing Ranges	Array	Easy	🔒
0164	Maximum Gap	Sort	Hard
0165	Compare Version Numbers	String	Medium
0166	Fraction to Recurring Decimal	Hash Table,Math	Medium
0167	Two Sum II - Input array is sorted	Array,Two Pointers,Binary Search	Easy
0168	Excel Sheet Column Title	Math	Easy
0169	Majority Element	Bit Manipulation,Array,Divide and Conquer	Easy
0170	Two Sum III - Data structure design	Design,Hash Table	Easy	🔒
0171	Excel Sheet Column Number	Math	Easy
0172	Factorial Trailing Zeroes	Math	Easy
0173	Binary Search Tree Iterator	Stack,Tree,Design	Medium
0174	Dungeon Game	Binary Search,Dynamic Programming	Hard
0175	Combine Two Tables		Easy
0176	Second Highest Salary		Easy
0177	Nth Highest Salary		Medium
0178	Rank Scores		Medium
0179	Largest Number	Sort	Medium
0180	Consecutive Numbers		Medium
0181	Employees Earning More Than Their Managers		Easy
0182	Duplicate Emails		Easy
0183	Customers Who Never Order		Easy
0184	Department Highest Salary		Medium
0185	Department Top Three Salaries		Hard
0186	Reverse Words in a String II	String	Medium	🔒
0187	Repeated DNA Sequences	Bit Manipulation,Hash Table	Medium
0188	Best Time to Buy and Sell Stock IV	Dynamic Programming	Hard
0189	Rotate Array	Array	Medium
0190	Reverse Bits	Bit Manipulation	Easy
0191	Number of 1 Bits	Bit Manipulation	Easy
0192	Word Frequency		Medium
0193	Valid Phone Numbers		Easy
0194	Transpose File		Medium
0195	Tenth Line		Easy
0196	Delete Duplicate Emails		Easy
0197	Rising Temperature		Easy
0198	House Robber	Dynamic Programming	Medium
0199	Binary Tree Right Side View	Tree,Depth-first Search,Breadth-first Search,Recursion,Queue	Medium
0200	Number of Islands	Depth-first Search,Breadth-first Search,Union Find	Medium
0201	Bitwise AND of Numbers Range	Bit Manipulation	Medium
0202	Happy Number	Hash Table,Math	Easy
0203	Remove Linked List Elements	Linked List	Easy
0204	Count Primes	Hash Table,Math	Easy
0205	Isomorphic Strings	Hash Table	Easy
0206	Reverse Linked List	Linked List	Easy
0207	Course Schedule	Depth-first Search,Breadth-first Search,Graph,Topological Sort	Medium
0208	Implement Trie (Prefix Tree)	Design,Trie	Medium
0209	Minimum Size Subarray Sum	Array,Two Pointers,Binary Search	Medium
0210	Course Schedule II	Depth-first Search,Breadth-first Search,Graph,Topological Sort	Medium
0211	Design Add and Search Words Data Structure	Depth-first Search,Design,Trie,Backtracking	Medium
0212	Word Search II	Trie,Backtracking	Hard
0213	House Robber II	Dynamic Programming	Medium
0214	Shortest Palindrome	String	Hard
0215	Kth Largest Element in an Array	Heap,Divide and Conquer	Medium
0216	Combination Sum III	Array,Backtracking	Medium
0217	Contains Duplicate	Array,Hash Table	Easy
0218	The Skyline Problem	Heap,Binary Indexed Tree,Segment Tree,Divide and Conquer,Line Sweep	Hard
0219	Contains Duplicate II	Array,Hash Table	Easy
0220	Contains Duplicate III	Sort,Ordered Map	Medium
0221	Maximal Square	Dynamic Programming	Medium
0222	Count Complete Tree Nodes	Tree,Binary Search	Medium
0223	Rectangle Area	Math	Medium
0224	Basic Calculator	Stack,Math	Hard
0225	Implement Stack using Queues	Stack,Design	Easy
0226	Invert Binary Tree	Tree	Easy
0227	Basic Calculator II	Stack,String	Medium
0228	Summary Ranges	Array	Easy
0229	Majority Element II	Array	Medium
0230	Kth Smallest Element in a BST	Tree,Binary Search	Medium
0231	Power of Two	Bit Manipulation,Math	Easy
0232	Implement Queue using Stacks	Stack,Design	Easy
0233	Number of Digit One	Math	Hard
0234	Palindrome Linked List	Linked List,Two Pointers	Easy
0235	Lowest Common Ancestor of a Binary Search Tree	Tree	Easy
0236	Lowest Common Ancestor of a Binary Tree	Tree	Medium
0237	Delete Node in a Linked List	Linked List	Easy
0238	Product of Array Except Self	Array	Medium
0239	Sliding Window Maximum	Heap,Sliding Window	Hard
0240	Search a 2D Matrix II	Binary Search,Divide and Conquer	Medium
0241	Different Ways to Add Parentheses	Divide and Conquer	Medium
0242	Valid Anagram	Sort,Hash Table	Easy
0243	Shortest Word Distance	Array	Easy	🔒
0244	Shortest Word Distance II	Design,Hash Table	Medium	🔒
0245	Shortest Word Distance III	Array	Medium	🔒
0246	Strobogrammatic Number	Hash Table,Math	Easy	🔒
0247	Strobogrammatic Number II	Recursion,Math	Medium	🔒
0248	Strobogrammatic Number III	Recursion,Math	Hard	🔒
0249	Group Shifted Strings	Hash Table,String	Medium	🔒
0250	Count Univalue Subtrees	Tree	Medium	🔒
0251	Flatten 2D Vector	Design	Medium	🔒
0252	Meeting Rooms	Sort	Easy	🔒
0253	Meeting Rooms II	Heap,Greedy,Sort	Medium	🔒
0254	Factor Combinations	Backtracking	Medium	🔒
0255	Verify Preorder Sequence in Binary Search Tree	Stack,Tree	Medium	🔒
0256	Paint House	Dynamic Programming	Medium	🔒
0257	Binary Tree Paths	Tree,Depth-first Search	Easy
0258	Add Digits	Math	Easy
0259	3Sum Smaller	Array,Two Pointers	Medium	🔒
0260	Single Number III	Bit Manipulation	Medium
0261	Graph Valid Tree	Depth-first Search,Breadth-first Search,Union Find,Graph	Medium	🔒
0262	Trips and Users		Hard
0263	Ugly Number	Math	Easy
0264	Ugly Number II	Heap,Math,Dynamic Programming	Medium
0265	Paint House II	Dynamic Programming	Hard	🔒
0266	Palindrome Permutation	Hash Table	Easy	🔒
0267	Palindrome Permutation II	Backtracking	Medium	🔒
0268	Missing Number	Bit Manipulation,Array,Math	Easy
0269	Alien Dictionary	Graph,Topological Sort	Hard	🔒
0270	Closest Binary Search Tree Value	Tree,Binary Search	Easy	🔒
0271	Encode and Decode Strings	String	Medium	🔒
0272	Closest Binary Search Tree Value II	Stack,Tree	Hard	🔒
0273	Integer to English Words	Math,String	Hard
0274	H-Index	Sort,Hash Table	Medium
0275	H-Index II	Binary Search	Medium
0276	Paint Fence	Dynamic Programming	Medium	🔒
0277	Find the Celebrity	Array	Medium	🔒
0278	First Bad Version	Binary Search	Easy
0279	Perfect Squares	Breadth-first Search,Math,Dynamic Programming	Medium
0280	Wiggle Sort	Sort,Array	Medium	🔒
0281	Zigzag Iterator	Design	Medium	🔒
0282	Expression Add Operators	Divide and Conquer	Hard
0283	Move Zeroes	Array,Two Pointers	Easy
0284	Peeking Iterator	Design	Medium
0285	Inorder Successor in BST	Tree	Medium	🔒
0286	Walls and Gates	Breadth-first Search	Medium	🔒
0287	Find the Duplicate Number	Array,Two Pointers,Binary Search	Medium
0288	Unique Word Abbreviation	Design,Hash Table	Medium	🔒
0289	Game of Life	Array	Medium
0290	Word Pattern	Hash Table	Easy
0291	Word Pattern II	Backtracking	Medium	🔒
0292	Nim Game	Brainteaser,Minimax	Easy
0293	Flip Game	String	Easy	🔒
0294	Flip Game II	Minimax,Backtracking	Medium	🔒
0295	Find Median from Data Stream	Heap,Design	Hard
0296	Best Meeting Point	Sort,Math	Hard	🔒
0297	Serialize and Deserialize Binary Tree	Tree,Design	Hard
0298	Binary Tree Longest Consecutive Sequence	Tree	Medium	🔒
0299	Bulls and Cows	Hash Table	Medium
0300	Longest Increasing Subsequence	Binary Search,Dynamic Programming	Medium
0301	Remove Invalid Parentheses	Depth-first Search,Breadth-first Search	Hard
0302	Smallest Rectangle Enclosing Black Pixels	Binary Search	Hard	🔒
0303	Range Sum Query - Immutable	Dynamic Programming	Easy
0304	Range Sum Query 2D - Immutable	Dynamic Programming	Medium
0305	Number of Islands II	Union Find	Hard	🔒
0306	Additive Number	Backtracking	Medium
0307	Range Sum Query - Mutable	Binary Indexed Tree,Segment Tree	Medium
0308	Range Sum Query 2D - Mutable	Binary Indexed Tree,Segment Tree	Hard	🔒
0309	Best Time to Buy and Sell Stock with Cooldown	Dynamic Programming	Medium
0310	Minimum Height Trees	Breadth-first Search,Graph	Medium
0311	Sparse Matrix Multiplication	Hash Table	Medium	🔒
0312	Burst Balloons	Divide and Conquer,Dynamic Programming	Hard
0313	Super Ugly Number	Heap,Math	Medium
0314	Binary Tree Vertical Order Traversal	Depth-first Search,Breadth-first Search	Medium	🔒
0315	Count of Smaller Numbers After Self	Sort,Binary Indexed Tree,Segment Tree,Binary Search,Divide and Conquer	Hard
0316	Remove Duplicate Letters	Stack,Greedy,String	Medium
0317	Shortest Distance from All Buildings	Breadth-first Search	Hard	🔒
0318	Maximum Product of Word Lengths	Bit Manipulation	Medium
0319	Bulb Switcher	Brainteaser,Math	Medium
0320	Generalized Abbreviation	Bit Manipulation,Backtracking	Medium	🔒
0321	Create Maximum Number	Greedy,Dynamic Programming	Hard
0322	Coin Change	Dynamic Programming	Medium
0323	Number of Connected Components in an Undirected Graph	Depth-first Search,Breadth-first Search,Union Find,Graph	Medium	🔒
0324	Wiggle Sort II	Sort	Medium
0325	Maximum Size Subarray Sum Equals k	Hash Table	Medium	🔒
0326	Power of Three	Math	Easy
0327	Count of Range Sum	Sort,Binary Indexed Tree,Segment Tree,Binary Search,Divide and Conquer	Hard
0328	Odd Even Linked List	Linked List	Medium
0329	Longest Increasing Path in a Matrix	Depth-first Search,Topological Sort,Memoization	Hard
0330	Patching Array	Greedy	Hard
0331	Verify Preorder Serialization of a Binary Tree	Stack	Medium
0332	Reconstruct Itinerary	Depth-first Search,Graph	Medium
0333	Largest BST Subtree	Tree	Medium	🔒
0334	Increasing Triplet Subsequence		Medium
0335	Self Crossing	Math	Hard
0336	Palindrome Pairs	Trie,Hash Table,String	Hard
0337	House Robber III	Tree,Depth-first Search,Dynamic Programming	Medium
0338	Counting Bits	Bit Manipulation,Dynamic Programming	Easy
0339	Nested List Weight Sum	Depth-first Search,Breadth-first Search	Medium	🔒
0340	Longest Substring with At Most K Distinct Characters	Hash Table,Two Pointers,String,Sliding Window	Medium	🔒
0341	Flatten Nested List Iterator	Stack,Design	Medium
0342	Power of Four	Bit Manipulation	Easy
0343	Integer Break	Math,Dynamic Programming	Medium
0344	Reverse String	Two Pointers,String	Easy
0345	Reverse Vowels of a String	Two Pointers,String	Easy
0346	Moving Average from Data Stream	Design,Queue	Easy	🔒
0347	Top K Frequent Elements	Heap,Hash Table	Medium
0348	Design Tic-Tac-Toe	Design	Medium	🔒
0349	Intersection of Two Arrays	Sort,Hash Table,Two Pointers,Binary Search	Easy
0350	Intersection of Two Arrays II	Sort,Hash Table,Two Pointers,Binary Search	Easy
0351	Android Unlock Patterns	Dynamic Programming,Backtracking	Medium	🔒
0352	Data Stream as Disjoint Intervals	Binary Search,Ordered Map	Hard
0353	Design Snake Game	Design,Queue	Medium	🔒
0354	Russian Doll Envelopes	Binary Search,Dynamic Programming	Hard
0355	Design Twitter	Heap,Design,Hash Table	Medium
0356	Line Reflection	Hash Table,Math	Medium	🔒
0357	Count Numbers with Unique Digits	Math,Dynamic Programming,Backtracking	Medium
0358	Rearrange String k Distance Apart	Heap,Greedy,Hash Table	Hard	🔒
0359	Logger Rate Limiter	Design,Hash Table	Easy	🔒
0360	Sort Transformed Array	Sort,Math,Two Pointers	Medium	🔒
0361	Bomb Enemy	Dynamic Programming	Medium	🔒
0362	Design Hit Counter	Design	Medium	🔒
0363	Max Sum of Rectangle No Larger Than K	Queue,Binary Search,Dynamic Programming	Hard
0364	Nested List Weight Sum II	Depth-first Search	Medium	🔒
0365	Water and Jug Problem	Math	Medium
0366	Find Leaves of Binary Tree	Tree,Depth-first Search	Medium	🔒
0367	Valid Perfect Square	Math,Binary Search	Easy
0368	Largest Divisible Subset	Math,Dynamic Programming	Medium
0369	Plus One Linked List	Recursion,Linked List	Medium	🔒
0370	Range Addition	Array	Medium	🔒
0371	Sum of Two Integers	Bit Manipulation	Medium
0372	Super Pow	Math	Medium
0373	Find K Pairs with Smallest Sums	Heap	Medium
0374	Guess Number Higher or Lower	Binary Search	Easy
0375	Guess Number Higher or Lower II	Minimax,Dynamic Programming	Medium
0376	Wiggle Subsequence	Greedy,Dynamic Programming	Medium
0377	Combination Sum IV	Dynamic Programming	Medium
0378	Kth Smallest Element in a Sorted Matrix	Heap,Binary Search	Medium
0379	Design Phone Directory	Design,Linked List	Medium	🔒
0380	Insert Delete GetRandom O(1)	Design,Array,Hash Table	Medium
0381	Insert Delete GetRandom O(1) - Duplicates allowed	Design,Array,Hash Table	Hard
0382	Linked List Random Node	Reservoir Sampling	Medium
0383	Ransom Note	String	Easy
0384	Shuffle an Array		Medium
0385	Mini Parser	Stack,String	Medium
0386	Lexicographical Numbers		Medium
0387	First Unique Character in a String	Hash Table,String	Easy
0388	Longest Absolute File Path		Medium
0389	Find the Difference	Bit Manipulation,Hash Table	Easy
0390	Elimination Game		Medium
0391	Perfect Rectangle	Line Sweep	Hard
0392	Is Subsequence	Greedy,Binary Search,Dynamic Programming	Easy
0393	UTF-8 Validation	Bit Manipulation	Medium
0394	Decode String	Stack,Depth-first Search	Medium
0395	Longest Substring with At Least K Repeating Characters	Recursion,Divide and Conquer,Sliding Window	Medium
0396	Rotate Function	Math	Medium
0397	Integer Replacement	Bit Manipulation,Math	Medium
0398	Random Pick Index	Reservoir Sampling	Medium
0399	Evaluate Division	Union Find,Graph	Medium
0400	Nth Digit	Math	Medium
0401	Binary Watch	Bit Manipulation,Backtracking	Easy
0402	Remove K Digits	Stack,Greedy	Medium
0403	Frog Jump	Dynamic Programming	Hard
0404	Sum of Left Leaves	Tree	Easy
0405	Convert a Number to Hexadecimal	Bit Manipulation	Easy
0406	Queue Reconstruction by Height	Greedy	Medium
0407	Trapping Rain Water II	Heap,Breadth-first Search	Hard
0408	Valid Word Abbreviation	String	Easy	🔒
0409	Longest Palindrome	Hash Table	Easy
0410	Split Array Largest Sum	Binary Search,Dynamic Programming	Hard
0411	Minimum Unique Word Abbreviation	Bit Manipulation,Backtracking	Hard	🔒
0412	Fizz Buzz		Easy
0413	Arithmetic Slices	Math,Dynamic Programming	Medium
0414	Third Maximum Number	Array	Easy
0415	Add Strings	String	Easy
0416	Partition Equal Subset Sum	Dynamic Programming	Medium
0417	Pacific Atlantic Water Flow	Depth-first Search,Breadth-first Search	Medium
0418	Sentence Screen Fitting	Dynamic Programming	Medium	🔒
0419	Battleships in a Board		Medium
0420	Strong Password Checker		Hard
0421	Maximum XOR of Two Numbers in an Array	Bit Manipulation,Trie	Medium
0422	Valid Word Square		Easy	🔒
0423	Reconstruct Original Digits from English	Math	Medium
0424	Longest Repeating Character Replacement	Two Pointers,Sliding Window	Medium
0425	Word Squares	Trie,Backtracking	Hard	🔒
0426	Convert Binary Search Tree to Sorted Doubly Linked List	Tree,Linked List,Divide and Conquer	Medium	🔒
0427	Construct Quad Tree		Medium
0428	Serialize and Deserialize N-ary Tree	Tree	Hard	🔒
0429	N-ary Tree Level Order Traversal	Tree,Breadth-first Search	Medium
0430	Flatten a Multilevel Doubly Linked List	Depth-first Search,Linked List	Medium
0431	Encode N-ary Tree to Binary Tree	Tree	Hard	🔒
0432	All O`one Data Structure	Design	Hard
0433	Minimum Genetic Mutation		Medium
0434	Number of Segments in a String	String	Easy
0435	Non-overlapping Intervals	Greedy	Medium
0436	Find Right Interval	Binary Search	Medium
0437	Path Sum III	Tree	Medium
0438	Find All Anagrams in a String	Hash Table	Medium
0439	Ternary Expression Parser	Stack,Depth-first Search	Medium	🔒
0440	K-th Smallest in Lexicographical Order		Hard
0441	Arranging Coins	Math,Binary Search	Easy
0442	Find All Duplicates in an Array	Array	Medium
0443	String Compression	String	Medium
0444	Sequence Reconstruction	Graph,Topological Sort	Medium	🔒
0445	Add Two Numbers II	Linked List	Medium
0446	Arithmetic Slices II - Subsequence	Dynamic Programming	Hard
0447	Number of Boomerangs	Hash Table,Math	Medium
0448	Find All Numbers Disappeared in an Array	Array	Easy
0449	Serialize and Deserialize BST	Tree	Medium
0450	Delete Node in a BST	Tree	Medium
0451	Sort Characters By Frequency	Heap,Hash Table	Medium
0452	Minimum Number of Arrows to Burst Balloons	Greedy,Sort	Medium
0453	Minimum Moves to Equal Array Elements	Math	Easy
0454	4Sum II	Hash Table,Binary Search	Medium
0455	Assign Cookies	Greedy	Easy
0456	132 Pattern	Stack	Medium
0457	Circular Array Loop	Array,Two Pointers	Medium
0458	Poor Pigs	Math	Hard
0459	Repeated Substring Pattern	String	Easy
0460	LFU Cache	Design	Hard
0461	Hamming Distance	Bit Manipulation	Easy
0462	Minimum Moves to Equal Array Elements II	Math	Medium
0463	Island Perimeter	Hash Table	Easy
0464	Can I Win	Minimax,Dynamic Programming	Medium
0465	Optimal Account Balancing		Hard	🔒
0466	Count The Repetitions	Dynamic Programming	Hard
0467	Unique Substrings in Wraparound String	Dynamic Programming	Medium
0468	Validate IP Address	String	Medium
0469	Convex Polygon	Math	Medium	🔒
0470	Implement Rand10() Using Rand7()	Random,Rejection Sampling	Medium
0471	Encode String with Shortest Length	Dynamic Programming	Hard	🔒
0472	Concatenated Words	Depth-first Search,Trie,Dynamic Programming	Hard
0473	Matchsticks to Square	Depth-first Search	Medium
0474	Ones and Zeroes	Dynamic Programming	Medium
0475	Heaters	Binary Search	Medium
0476	Number Complement	Bit Manipulation	Easy
0477	Total Hamming Distance	Bit Manipulation	Medium
0478	Generate Random Point in a Circle	Math,Random,Rejection Sampling	Medium
0479	Largest Palindrome Product		Hard
0480	Sliding Window Median	Sliding Window	Hard
0481	Magical String		Medium
0482	License Key Formatting		Easy
0483	Smallest Good Base	Math,Binary Search	Hard
0484	Find Permutation	Greedy	Medium	🔒
0485	Max Consecutive Ones	Array	Easy
0486	Predict the Winner	Minimax,Dynamic Programming	Medium
0487	Max Consecutive Ones II	Two Pointers	Medium	🔒
0488	Zuma Game	Depth-first Search	Hard
0489	Robot Room Cleaner	Depth-first Search	Hard	🔒
0490	The Maze	Depth-first Search,Breadth-first Search	Medium	🔒
0491	Increasing Subsequences	Depth-first Search	Medium
0492	Construct the Rectangle	Math	Easy
0493	Reverse Pairs	Sort,Binary Indexed Tree,Segment Tree,Binary Search,Divide and Conquer	Hard
0494	Target Sum	Depth-first Search,Dynamic Programming	Medium
0495	Teemo Attacking	Array	Easy
0496	Next Greater Element I	Stack	Easy
0497	Random Point in Non-overlapping Rectangles	Binary Search,Random	Medium
0498	Diagonal Traverse		Medium
0499	The Maze III	Depth-first Search,Breadth-first Search	Hard	🔒
0500	Keyboard Row	Hash Table	Easy
0501	Find Mode in Binary Search Tree	Tree	Easy
0502	IPO	Heap,Greedy	Hard
0503	Next Greater Element II	Stack	Medium
0504	Base 7		Easy
0505	The Maze II	Depth-first Search,Breadth-first Search	Medium	🔒
0506	Relative Ranks		Easy
0507	Perfect Number	Math	Easy
0508	Most Frequent Subtree Sum	Tree,Hash Table	Medium
0509	Fibonacci Number	Array	Easy
0510	Inorder Successor in BST II	Tree	Medium	🔒
0511	Game Play Analysis I		Easy	🔒
0512	Game Play Analysis II		Easy	🔒
0513	Find Bottom Left Tree Value	Tree,Depth-first Search,Breadth-first Search	Medium
0514	Freedom Trail	Depth-first Search,Divide and Conquer,Dynamic Programming	Hard
0515	Find Largest Value in Each Tree Row	Tree,Depth-first Search,Breadth-first Search	Medium
0516	Longest Palindromic Subsequence	Dynamic Programming	Medium
0517	Super Washing Machines	Math,Dynamic Programming	Hard
0518	Coin Change 2		Medium
0519	Random Flip Matrix	Random	Medium
0520	Detect Capital	String	Easy
0521	Longest Uncommon Subsequence I	Brainteaser,String	Easy
0522	Longest Uncommon Subsequence II	String	Medium
0523	Continuous Subarray Sum	Math,Dynamic Programming	Medium
0524	Longest Word in Dictionary through Deleting	Sort,Two Pointers	Medium
0525	Contiguous Array	Hash Table	Medium
0526	Beautiful Arrangement	Depth-first Search,Backtracking	Medium
0527	Word Abbreviation	Sort,String	Hard	🔒
0528	Random Pick with Weight	Binary Search,Random	Medium
0529	Minesweeper	Depth-first Search,Breadth-first Search	Medium
0530	Minimum Absolute Difference in BST	Tree	Easy
0531	Lonely Pixel I	Depth-first Search,Array	Medium	🔒
0532	K-diff Pairs in an Array	Array,Two Pointers	Medium
0533	Lonely Pixel II	Array	Medium	🔒
0534	Game Play Analysis III		Medium	🔒
0535	Encode and Decode TinyURL	Hash Table,Math	Medium
0536	Construct Binary Tree from String	Tree,String	Medium	🔒
0537	Complex Number Multiplication	Math,String	Medium
0538	Convert BST to Greater Tree	Tree,Depth-first Search,Binary Search Tree,Recursion	Medium
0539	Minimum Time Difference	String	Medium
0540	Single Element in a Sorted Array	Binary Search	Medium
0541	Reverse String II	String	Easy
0542	01 Matrix	Depth-first Search,Breadth-first Search	Medium
0543	Diameter of Binary Tree	Tree	Easy
0544	Output Contest Matches	Recursion,String	Medium	🔒
0545	Boundary of Binary Tree	Tree	Medium	🔒
0546	Remove Boxes	Depth-first Search,Dynamic Programming	Hard
0547	Number of Provinces	Depth-first Search,Union Find	Medium
0548	Split Array with Equal Sum	Array	Medium	🔒
0549	Binary Tree Longest Consecutive Sequence II	Tree	Medium	🔒
0550	Game Play Analysis IV		Medium	🔒
0551	Student Attendance Record I	String	Easy
0552	Student Attendance Record II	Dynamic Programming	Hard
0553	Optimal Division	Math,String	Medium
0554	Brick Wall	Hash Table	Medium
0555	Split Concatenated Strings	String	Medium	🔒
0556	Next Greater Element III	String	Medium
0557	Reverse Words in a String III	String	Easy
0558	Logical OR of Two Binary Grids Represented as Quad-Trees		Medium
0559	Maximum Depth of N-ary Tree	Tree,Depth-first Search,Breadth-first Search	Easy
0560	Subarray Sum Equals K	Array,Hash Table	Medium
0561	Array Partition I	Array	Easy
0562	Longest Line of Consecutive One in Matrix	Array,Dynamic Programming	Medium	🔒
0563	Binary Tree Tilt	Tree,Depth-first Search,Recursion	Easy
0564	Find the Closest Palindrome	String	Hard
0565	Array Nesting	Array	Medium
0566	Reshape the Matrix	Array	Easy
0567	Permutation in String	Two Pointers,Sliding Window	Medium
0568	Maximum Vacation Days	Dynamic Programming	Hard	🔒
0569	Median Employee Salary		Hard	🔒
0570	Managers with at Least 5 Direct Reports		Medium	🔒
0571	Find Median Given Frequency of Numbers		Hard	🔒
0572	Subtree of Another Tree	Tree	Easy
0573	Squirrel Simulation	Math	Medium	🔒
0574	Winning Candidate		Medium	🔒
0575	Distribute Candies	Hash Table	Easy
0576	Out of Boundary Paths	Depth-first Search,Dynamic Programming	Medium
0577	Employee Bonus		Easy	🔒
0578	Get Highest Answer Rate Question		Medium	🔒
0579	Find Cumulative Salary of an Employee		Hard	🔒
0580	Count Student Number in Departments		Medium	🔒
0581	Shortest Unsorted Continuous Subarray	Array	Medium
0582	Kill Process	Tree,Queue	Medium	🔒
0583	Delete Operation for Two Strings	String	Medium
0584	Find Customer Referee		Easy	🔒
0585	Investments in 2016		Medium	🔒
0586	Customer Placing the Largest Number of Orders		Easy	🔒
0587	Erect the Fence	Geometry	Hard
0588	Design In-Memory File System	Design	Hard	🔒
0589	N-ary Tree Preorder Traversal	Tree	Easy
0590	N-ary Tree Postorder Traversal	Tree	Easy
0591	Tag Validator	Stack,String	Hard
0592	Fraction Addition and Subtraction	Math	Medium
0593	Valid Square	Math	Medium
0594	Longest Harmonious Subsequence	Hash Table	Easy
0595	Big Countries		Easy
0596	Classes More Than 5 Students		Easy
0597	Friend Requests I Overall Acceptance Rate		Easy	🔒
0598	Range Addition II	Math	Easy
0599	Minimum Index Sum of Two Lists	Hash Table	Easy
0600	Non-negative Integers without Consecutive Ones	Dynamic Programming	Hard
0601	Human Traffic of Stadium		Hard
0602	Friend Requests II Who Has the Most Friends		Medium	🔒
0603	Consecutive Available Seats		Easy	🔒
0604	Design Compressed String Iterator	Design	Easy	🔒
0605	Can Place Flowers	Greedy,Array	Easy
0606	Construct String from Binary Tree	Tree,String	Easy
0607	Sales Person		Easy	🔒
0608	Tree Node		Medium	🔒
0609	Find Duplicate File in System	Hash Table,String	Medium
0610	Triangle Judgement		Easy	🔒
0611	Valid Triangle Number	Array	Medium
0612	Shortest Distance in a Plane		Medium	🔒
0613	Shortest Distance in a Line		Easy	🔒
0614	Second Degree Follower		Medium	🔒
0615	Average Salary Departments VS Company		Hard	🔒
0616	Add Bold Tag in String	String	Medium	🔒
0617	Merge Two Binary Trees	Tree	Easy
0618	Students Report By Geography		Hard	🔒
0619	Biggest Single Number		Easy	🔒
0620	Not Boring Movies		Easy
0621	Task Scheduler	Greedy,Queue,Array	Medium
0622	Design Circular Queue	Design,Queue	Medium
0623	Add One Row to Tree	Tree	Medium
0624	Maximum Distance in Arrays	Array,Hash Table	Medium	🔒
0625	Minimum Factorization	Recursion,Math	Medium	🔒
0626	Exchange Seats		Medium
0627	Swap Salary		Easy
0628	Maximum Product of Three Numbers	Array,Math	Easy
0629	K Inverse Pairs Array	Dynamic Programming	Hard
0630	Course Schedule III	Greedy	Hard
0631	Design Excel Sum Formula	Design	Hard	🔒
0632	Smallest Range Covering Elements from K Lists	Hash Table,Two Pointers,String	Hard
0633	Sum of Square Numbers	Math	Medium
0634	Find the Derangement of An Array	Math	Medium	🔒
0635	Design Log Storage System	Design,String	Medium	🔒
0636	Exclusive Time of Functions	Stack	Medium
0637	Average of Levels in Binary Tree	Tree	Easy
0638	Shopping Offers	Depth-first Search,Dynamic Programming	Medium
0639	Decode Ways II	Dynamic Programming	Hard
0640	Solve the Equation	Math	Medium
0641	Design Circular Deque	Design,Queue	Medium
0642	Design Search Autocomplete System	Design,Trie	Hard	🔒
0643	Maximum Average Subarray I	Array	Easy
0644	Maximum Average Subarray II	Array,Binary Search	Hard	🔒
0645	Set Mismatch	Hash Table,Math	Easy
0646	Maximum Length of Pair Chain	Dynamic Programming	Medium
0647	Palindromic Substrings	String,Dynamic Programming	Medium
0648	Replace Words	Trie,Hash Table	Medium
0649	Dota2 Senate	Greedy	Medium
0650	2 Keys Keyboard	Dynamic Programming	Medium
0651	4 Keys Keyboard	Greedy,Math,Dynamic Programming	Medium	🔒
0652	Find Duplicate Subtrees	Tree	Medium
0653	Two Sum IV - Input is a BST	Tree	Easy
0654	Maximum Binary Tree	Tree	Medium
0655	Print Binary Tree	Tree	Medium
0656	Coin Path	Dynamic Programming	Hard	🔒
0657	Robot Return to Origin	String	Easy
0658	Find K Closest Elements	Binary Search	Medium
0659	Split Array into Consecutive Subsequences	Heap,Greedy	Medium
0660	Remove 9	Math	Hard	🔒
0661	Image Smoother	Array	Easy
0662	Maximum Width of Binary Tree	Tree	Medium
0663	Equal Tree Partition	Tree	Medium	🔒
0664	Strange Printer	Depth-first Search,Dynamic Programming	Hard
0665	Non-decreasing Array	Array	Easy
0666	Path Sum IV	Tree	Medium	🔒
0667	Beautiful Arrangement II	Array	Medium
0668	Kth Smallest Number in Multiplication Table	Binary Search	Hard
0669	Trim a Binary Search Tree	Tree,Recursion	Medium
0670	Maximum Swap	Array,Math	Medium
0671	Second Minimum Node In a Binary Tree	Tree	Easy
0672	Bulb Switcher II	Math	Medium
0673	Number of Longest Increasing Subsequence	Dynamic Programming	Medium
0674	Longest Continuous Increasing Subsequence	Array	Easy
0675	Cut Off Trees for Golf Event	Breadth-first Search	Hard
0676	Implement Magic Dictionary	Trie,Hash Table	Medium
0677	Map Sum Pairs	Trie	Medium
0678	Valid Parenthesis String	String	Medium
0679	24 Game	Depth-first Search	Hard
0680	Valid Palindrome II	String	Easy
0681	Next Closest Time	String	Medium	🔒
0682	Baseball Game	Stack	Easy
0683	K Empty Slots	Ordered Map	Hard	🔒
0684	Redundant Connection	Tree,Union Find,Graph	Medium
0685	Redundant Connection II	Tree,Depth-first Search,Union Find,Graph	Hard
0686	Repeated String Match	String	Medium
0687	Longest Univalue Path	Tree,Recursion	Medium
0688	Knight Probability in Chessboard	Dynamic Programming	Medium
0689	Maximum Sum of 3 Non-Overlapping Subarrays	Array,Dynamic Programming	Hard
0690	Employee Importance	Depth-first Search,Breadth-first Search,Hash Table	Easy
0691	Stickers to Spell Word	Dynamic Programming,Backtracking	Hard
0692	Top K Frequent Words	Heap,Trie,Hash Table	Medium
0693	Binary Number with Alternating Bits	Bit Manipulation	Easy
0694	Number of Distinct Islands	Depth-first Search,Breadth-first Search,Hash Table	Medium	🔒
0695	Max Area of Island	Depth-first Search,Array	Medium
0696	Count Binary Substrings	String	Easy
0697	Degree of an Array	Array	Easy
0698	Partition to K Equal Sum Subsets	Recursion,Dynamic Programming	Medium
0699	Falling Squares	Segment Tree,Ordered Map	Hard
0700	Search in a Binary Search Tree	Tree	Easy
0701	Insert into a Binary Search Tree	Tree	Medium
0702	Search in a Sorted Array of Unknown Size	Binary Search	Medium	🔒
0703	Kth Largest Element in a Stream	Heap,Design	Easy
0704	Binary Search	Binary Search	Easy
0705	Design HashSet	Design,Hash Table	Easy
0706	Design HashMap	Design,Hash Table	Easy
0707	Design Linked List	Design,Linked List	Medium
0708	Insert into a Sorted Circular Linked List	Linked List	Medium	🔒
0709	To Lower Case	String	Easy
0710	Random Pick with Blacklist	Sort,Hash Table,Binary Search,Random	Hard
0711	Number of Distinct Islands II	Depth-first Search,Hash Table	Hard	🔒
0712	Minimum ASCII Delete Sum for Two Strings	Dynamic Programming	Medium
0713	Subarray Product Less Than K	Array,Two Pointers	Medium
0714	Best Time to Buy and Sell Stock with Transaction Fee	Greedy,Array,Dynamic Programming	Medium
0715	Range Module	Segment Tree,Ordered Map	Hard
0716	Max Stack	Design	Easy	🔒
0717	1-bit and 2-bit Characters	Array	Easy
0718	Maximum Length of Repeated Subarray	Array,Hash Table,Binary Search,Dynamic Programming	Medium
0719	Find K-th Smallest Pair Distance	Heap,Array,Binary Search	Hard
0720	Longest Word in Dictionary	Trie,Hash Table	Easy
0721	Accounts Merge	Depth-first Search,Union Find	Medium
0722	Remove Comments	String	Medium
0723	Candy Crush	Array,Two Pointers	Medium	🔒
0724	Find Pivot Index	Array	Easy
0725	Split Linked List in Parts	Linked List	Medium
0726	Number of Atoms	Stack,Recursion,Hash Table	Hard
0727	Minimum Window Subsequence	Dynamic Programming,Sliding Window	Hard	🔒
0728	Self Dividing Numbers	Math	Easy
0729	My Calendar I	Array	Medium
0730	Count Different Palindromic Subsequences	String,Dynamic Programming	Hard
0731	My Calendar II	Ordered Map	Medium
0732	My Calendar III	Segment Tree,Ordered Map	Hard
0733	Flood Fill	Depth-first Search	Easy
0734	Sentence Similarity	Hash Table	Easy	🔒
0735	Asteroid Collision	Stack	Medium
0736	Parse Lisp Expression	String	Hard
0737	Sentence Similarity II	Depth-first Search,Union Find	Medium	🔒
0738	Monotone Increasing Digits	Greedy	Medium
0739	Daily Temperatures	Stack,Hash Table	Medium
0740	Delete and Earn	Dynamic Programming	Medium
0741	Cherry Pickup	Dynamic Programming	Hard
0742	Closest Leaf in a Binary Tree	Tree	Medium	🔒
0743	Network Delay Time	Heap,Depth-first Search,Breadth-first Search,Graph	Medium
0744	Find Smallest Letter Greater Than Target	Binary Search	Easy
0745	Prefix and Suffix Search	Trie	Hard
0746	Min Cost Climbing Stairs	Array,Dynamic Programming	Easy
0747	Largest Number At Least Twice of Others	Array	Easy
0748	Shortest Completing Word	Hash Table	Easy
0749	Contain Virus	Depth-first Search	Hard
0750	Number Of Corner Rectangles	Dynamic Programming	Medium	🔒
0751	IP to CIDR	Bit Manipulation	Medium	🔒
0752	Open the Lock	Breadth-first Search	Medium
0753	Cracking the Safe	Depth-first Search,Math	Hard
0754	Reach a Number	Math	Medium
0755	Pour Water	Array	Medium	🔒
0756	Pyramid Transition Matrix	Bit Manipulation,Depth-first Search	Medium
0757	Set Intersection Size At Least Two	Greedy	Hard
0758	Bold Words in String	String	Medium	🔒
0759	Employee Free Time	Heap,Greedy	Hard	🔒
0760	Find Anagram Mappings	Hash Table	Easy	🔒
0761	Special Binary String	Recursion,String	Hard
0762	Prime Number of Set Bits in Binary Representation	Bit Manipulation	Easy
0763	Partition Labels	Greedy,Two Pointers	Medium
0764	Largest Plus Sign	Dynamic Programming	Medium
0765	Couples Holding Hands	Greedy,Union Find,Graph	Hard
0766	Toeplitz Matrix	Array	Easy
0767	Reorganize String	Heap,Greedy,Sort,String	Medium
0768	Max Chunks To Make Sorted II	Array	Hard
0769	Max Chunks To Make Sorted	Array	Medium
0770	Basic Calculator IV	Stack,Hash Table,String	Hard
0771	Jewels and Stones	Hash Table	Easy
0772	Basic Calculator III	Stack,String	Hard	🔒
0773	Sliding Puzzle	Breadth-first Search	Hard
0774	Minimize Max Distance to Gas Station	Binary Search	Hard	🔒
0775	Global and Local Inversions	Array,Math	Medium
0776	Split BST	Tree,Recursion	Medium	🔒
0777	Swap Adjacent in LR String	Brainteaser	Medium
0778	Swim in Rising Water	Heap,Depth-first Search,Union Find,Binary Search	Hard
0779	K-th Symbol in Grammar	Recursion	Medium
0780	Reaching Points	Math	Hard
0781	Rabbits in Forest	Hash Table,Math	Medium
0782	Transform to Chessboard	Array,Math	Hard
0783	Minimum Distance Between BST Nodes	Tree,Depth-first Search,Recursion	Easy
0784	Letter Case Permutation	Bit Manipulation,Backtracking	Medium
0785	Is Graph Bipartite	Depth-first Search,Breadth-first Search,Graph	Medium
0786	K-th Smallest Prime Fraction	Heap,Binary Search	Hard
0787	Cheapest Flights Within K Stops	Heap,Breadth-first Search,Dynamic Programming	Medium
0788	Rotated Digits	String	Easy
0789	Escape The Ghosts	Math	Medium
0790	Domino and Tromino Tiling	Dynamic Programming	Medium
0791	Custom Sort String	String	Medium
0792	Number of Matching Subsequences	Array	Medium
0793	Preimage Size of Factorial Zeroes Function	Binary Search	Hard
0794	Valid Tic-Tac-Toe State	Recursion,Math	Medium
0795	Number of Subarrays with Bounded Maximum	Array	Medium
0796	Rotate String		Easy
0797	All Paths From Source to Target	Depth-first Search,Graph,Backtracking	Medium
0798	Smallest Rotation with Highest Score		Hard
0799	Champagne Tower	Dynamic Programming	Medium
0800	Similar RGB Color	Math,String	Easy	🔒
0801	Minimum Swaps To Make Sequences Increasing	Dynamic Programming	Medium
0802	Find Eventual Safe States	Depth-first Search,Graph	Medium
0803	Bricks Falling When Hit	Union Find	Hard
0804	Unique Morse Code Words	String	Easy
0805	Split Array With Same Average	Math	Hard
0806	Number of Lines To Write String		Easy
0807	Max Increase to Keep City Skyline		Medium
0808	Soup Servings	Dynamic Programming	Medium
0809	Expressive Words	String	Medium
0810	Chalkboard XOR Game	Math	Hard
0811	Subdomain Visit Count	Hash Table	Easy
0812	Largest Triangle Area	Math	Easy
0813	Largest Sum of Averages	Dynamic Programming	Medium
0814	Binary Tree Pruning	Tree	Medium
0815	Bus Routes	Breadth-first Search	Hard
0816	Ambiguous Coordinates	String	Medium
0817	Linked List Components	Linked List	Medium
0818	Race Car	Heap,Dynamic Programming	Hard
0819	Most Common Word	String	Easy
0820	Short Encoding of Words		Medium
0821	Shortest Distance to a Character		Easy
0822	Card Flipping Game		Medium
0823	Binary Trees With Factors		Medium
0824	Goat Latin	String	Easy
0825	Friends Of Appropriate Ages	Array	Medium
0826	Most Profit Assigning Work	Two Pointers	Medium
0827	Making A Large Island	Depth-first Search,Breadth-first Search	Hard
0828	Count Unique Characters of All Substrings of a Given String	Two Pointers	Hard
0829	Consecutive Numbers Sum	Math	Hard
0830	Positions of Large Groups	Array	Easy
0831	Masking Personal Information	String	Medium
0832	Flipping an Image	Array	Easy
0833	Find And Replace in String	String	Medium
0834	Sum of Distances in Tree	Tree,Depth-first Search	Hard
0835	Image Overlap	Array	Medium
0836	Rectangle Overlap	Math	Easy
0837	New 21 Game	Dynamic Programming	Medium
0838	Push Dominoes	Two Pointers,Dynamic Programming	Medium
0839	Similar String Groups	Depth-first Search,Union Find,Graph	Hard
0840	Magic Squares In Grid	Array	Medium
0841	Keys and Rooms	Depth-first Search,Graph	Medium
0842	Split Array into Fibonacci Sequence	Greedy,String,Backtracking	Medium
0843	Guess the Word	Minimax	Hard
0844	Backspace String Compare	Stack,Two Pointers	Easy
0845	Longest Mountain in Array	Two Pointers	Medium
0846	Hand of Straights	Ordered Map	Medium
0847	Shortest Path Visiting All Nodes	Breadth-first Search,Dynamic Programming	Hard
0848	Shifting Letters	String	Medium
0849	Maximize Distance to Closest Person	Array	Medium
0850	Rectangle Area II	Segment Tree,Line Sweep	Hard
0851	Loud and Rich	Depth-first Search	Medium
0852	Peak Index in a Mountain Array	Binary Search	Easy
0853	Car Fleet	Sort	Medium
0854	K-Similar Strings	Breadth-first Search,Graph	Hard
0855	Exam Room	Ordered Map	Medium
0856	Score of Parentheses	Stack,String	Medium
0857	Minimum Cost to Hire K Workers	Heap	Hard
0858	Mirror Reflection	Math	Medium
0859	Buddy Strings	String	Easy
0860	Lemonade Change	Greedy	Easy
0861	Score After Flipping Matrix	Greedy	Medium
0862	Shortest Subarray with Sum at Least K	Queue,Binary Search	Hard
0863	All Nodes Distance K in Binary Tree	Tree,Depth-first Search,Breadth-first Search	Medium
0864	Shortest Path to Get All Keys	Heap,Breadth-first Search	Hard
0865	Smallest Subtree with all the Deepest Nodes	Tree,Depth-first Search,Breadth-first Search,Recursion	Medium
0866	Prime Palindrome	Math	Medium
0867	Transpose Matrix	Array	Easy
0868	Binary Gap	Math	Easy
0869	Reordered Power of 2	Math	Medium
0870	Advantage Shuffle	Greedy,Array	Medium
0871	Minimum Number of Refueling Stops	Heap,Dynamic Programming	Hard
0872	Leaf-Similar Trees	Tree,Depth-first Search	Easy
0873	Length of Longest Fibonacci Subsequence	Array,Dynamic Programming	Medium
0874	Walking Robot Simulation	Greedy	Easy
0875	Koko Eating Bananas	Binary Search	Medium
0876	Middle of the Linked List	Linked List	Easy
0877	Stone Game	Minimax,Math,Dynamic Programming	Medium
0878	Nth Magical Number	Math,Binary Search	Hard
0879	Profitable Schemes	Dynamic Programming	Hard
0880	Decoded String at Index	Stack	Medium
0881	Boats to Save People	Greedy,Two Pointers	Medium
0882	Reachable Nodes In Subdivided Graph	Heap,Breadth-first Search	Hard
0883	Projection Area of 3D Shapes	Math	Easy
0884	Uncommon Words from Two Sentences	Hash Table	Easy
0885	Spiral Matrix III	Math	Medium
0886	Possible Bipartition	Depth-first Search,Graph	Medium
0887	Super Egg Drop	Math,Binary Search,Dynamic Programming	Hard
0888	Fair Candy Swap	Array	Easy
0889	Construct Binary Tree from Preorder and Postorder Traversal	Tree	Medium
0890	Find and Replace Pattern	String	Medium
0891	Sum of Subsequence Widths	Array,Math	Hard
0892	Surface Area of 3D Shapes	Geometry,Math	Easy
0893	Groups of Special-Equivalent Strings	String	Easy
0894	All Possible Full Binary Trees	Tree,Recursion	Medium
0895	Maximum Frequency Stack	Stack,Hash Table	Hard
0896	Monotonic Array	Array	Easy
0897	Increasing Order Search Tree	Tree,Depth-first Search,Recursion	Easy
0898	Bitwise ORs of Subarrays	Bit Manipulation,Dynamic Programming	Medium
0899	Orderly Queue	Math,String	Hard
0900	RLE Iterator	Array	Medium
0901	Online Stock Span	Stack	Medium
0902	Numbers At Most N Given Digit Set	Math,Dynamic Programming	Hard
0903	Valid Permutations for DI Sequence	Divide and Conquer,Dynamic Programming	Hard
0904	Fruit Into Baskets	Two Pointers	Medium
0905	Sort Array By Parity	Array	Easy
0906	Super Palindromes	Math	Hard
0907	Sum of Subarray Minimums	Stack,Array	Medium
0908	Smallest Range I	Math	Easy
0909	Snakes and Ladders	Breadth-first Search	Medium
0910	Smallest Range II	Greedy,Math	Medium
0911	Online Election	Binary Search	Medium
0912	Sort an Array		Medium
0913	Cat and Mouse	Breadth-first Search,Minimax	Hard
0914	X of a Kind in a Deck of Cards	Array,Math	Easy
0915	Partition Array into Disjoint Intervals	Array	Medium
0916	Word Subsets	String	Medium
0917	Reverse Only Letters	String	Easy
0918	Maximum Sum Circular Subarray	Array	Medium
0919	Complete Binary Tree Inserter	Tree	Medium
0920	Number of Music Playlists	Dynamic Programming	Hard
0921	Minimum Add to Make Parentheses Valid	Stack,Greedy	Medium
0922	Sort Array By Parity II	Sort,Array	Easy
0923	3Sum With Multiplicity	Two Pointers	Medium
0924	Minimize Malware Spread	Depth-first Search,Union Find	Hard
0925	Long Pressed Name	Two Pointers,String	Easy
0926	Flip String to Monotone Increasing	Array	Medium
0927	Three Equal Parts	Greedy,Math,Binary Search	Hard
0928	Minimize Malware Spread II	Depth-first Search,Union Find,Graph	Hard
0929	Unique Email Addresses	String	Easy
0930	Binary Subarrays With Sum	Hash Table,Two Pointers	Medium
0931	Minimum Falling Path Sum	Dynamic Programming	Medium
0932	Beautiful Array	Divide and Conquer	Medium
0933	Number of Recent Calls	Queue	Easy
0934	Shortest Bridge	Depth-first Search,Breadth-first Search	Medium
0935	Knight Dialer	Dynamic Programming	Medium
0936	Stamping The Sequence	Greedy,String	Hard
0937	Reorder Data in Log Files	String	Easy
0938	Range Sum of BST	Tree,Depth-first Search,Recursion	Easy
0939	Minimum Area Rectangle	Hash Table	Medium
0940	Distinct Subsequences II	Dynamic Programming	Hard
0941	Valid Mountain Array	Array	Easy
0942	DI String Match	Math	Easy
0943	Find the Shortest Superstring	Dynamic Programming	Hard
0944	Delete Columns to Make Sorted	Greedy	Easy
0945	Minimum Increment to Make Array Unique	Array	Medium
0946	Validate Stack Sequences	Stack	Medium
0947	Most Stones Removed with Same Row or Column	Depth-first Search,Union Find	Medium
0948	Bag of Tokens	Greedy,Sort,Two Pointers	Medium
0949	Largest Time for Given Digits	Math	Medium
0950	Reveal Cards In Increasing Order	Array	Medium
0951	Flip Equivalent Binary Trees	Tree	Medium
0952	Largest Component Size by Common Factor	Union Find,Math	Hard
0953	Verifying an Alien Dictionary	Hash Table	Easy
0954	Array of Doubled Pairs	Array,Hash Table	Medium
0955	Delete Columns to Make Sorted II	Greedy	Medium
0956	Tallest Billboard	Dynamic Programming	Hard
0957	Prison Cells After N Days	Hash Table	Medium
0958	Check Completeness of a Binary Tree	Tree	Medium
0959	Regions Cut By Slashes	Depth-first Search,Union Find,Graph	Medium
0960	Delete Columns to Make Sorted III	Dynamic Programming	Hard
0961	N-Repeated Element in Size 2N Array	Hash Table	Easy
0962	Maximum Width Ramp	Array	Medium
0963	Minimum Area Rectangle II	Geometry,Math	Medium
0964	Least Operators to Express Number	Math,Dynamic Programming	Hard
0965	Univalued Binary Tree	Tree	Easy
0966	Vowel Spellchecker	Hash Table,String	Medium
0967	Numbers With Same Consecutive Differences	Depth-first Search,Breadth-first Search,Recursion,Backtracking	Medium
0968	Binary Tree Cameras	Tree,Depth-first Search,Dynamic Programming	Hard
0969	Pancake Sorting	Sort,Array	Medium
0970	Powerful Integers	Hash Table,Math	Medium
0971	Flip Binary Tree To Match Preorder Traversal	Tree,Depth-first Search	Medium
0972	Equal Rational Numbers	Math	Hard
0973	K Closest Points to Origin	Heap,Sort,Divide and Conquer	Medium
0974	Subarray Sums Divisible by K	Array,Hash Table	Medium
0975	Odd Even Jump	Stack,Dynamic Programming,Ordered Map	Hard
0976	Largest Perimeter Triangle	Sort,Math	Easy
0977	Squares of a Sorted Array	Array,Two Pointers	Easy
0978	Longest Turbulent Subarray	Array,Dynamic Programming,Sliding Window	Medium
0979	Distribute Coins in Binary Tree	Tree,Depth-first Search	Medium
0980	Unique Paths III	Depth-first Search,Backtracking	Hard
0981	Time Based Key-Value Store	Hash Table,Binary Search	Medium
0982	Triples with Bitwise AND Equal To Zero	Dynamic Programming	Hard
0983	Minimum Cost For Tickets	Dynamic Programming	Medium
0984	String Without AAA or BBB	Greedy	Medium
0985	Sum of Even Numbers After Queries	Array	Easy
0986	Interval List Intersections	Two Pointers	Medium
0987	Vertical Order Traversal of a Binary Tree	Tree,Depth-first Search,Breadth-first Search,Hash Table	Hard
0988	Smallest String Starting From Leaf	Tree,Depth-first Search	Medium
0989	Add to Array-Form of Integer	Array	Easy
0990	Satisfiability of Equality Equations	Union Find,Graph	Medium
0991	Broken Calculator	Greedy,Math	Medium
0992	Subarrays with K Different Integers	Hash Table,Two Pointers,Sliding Window	Hard
0993	Cousins in Binary Tree	Tree,Breadth-first Search	Easy
0994	Rotting Oranges	Breadth-first Search	Medium
0995	Minimum Number of K Consecutive Bit Flips	Greedy,Sliding Window	Hard
0996	Number of Squareful Arrays	Graph,Math,Backtracking	Hard
0997	Find the Town Judge	Graph	Easy
0998	Maximum Binary Tree II	Tree	Medium
0999	Available Captures for Rook	Array	Easy
1000	Minimum Cost to Merge Stones	Dynamic Programming	Hard
1001	Grid Illumination	Hash Table	Hard
1002	Find Common Characters	Array,Hash Table	Easy
1003	Check If Word Is Valid After Substitutions	Stack,String	Medium
1004	Max Consecutive Ones III	Two Pointers,Sliding Window	Medium
1005	Maximize Sum Of Array After K Negations	Greedy	Easy
1006	Clumsy Factorial	Math	Medium
1007	Minimum Domino Rotations For Equal Row	Greedy,Array	Medium
1008	Construct Binary Search Tree from Preorder Traversal	Tree	Medium
1009	Complement of Base 10 Integer	Math	Easy
1010	Pairs of Songs With Total Durations Divisible by 60	Array	Medium
1011	Capacity To Ship Packages Within D Days	Array,Binary Search	Medium
1012	Numbers With Repeated Digits	Math,Dynamic Programming	Hard
1013	Partition Array Into Three Parts With Equal Sum	Array	Easy
1014	Best Sightseeing Pair	Array	Medium
1015	Smallest Integer Divisible by K	Math	Medium
1016	Binary String With Substrings Representing 1 To N	String	Medium
1017	Convert to Base -2	Math	Medium
1018	Binary Prefix Divisible By 5	Array	Easy
1019	Next Greater Node In Linked List	Stack,Linked List	Medium
1020	Number of Enclaves	Depth-first Search	Medium
1021	Remove Outermost Parentheses	Stack	Easy
1022	Sum of Root To Leaf Binary Numbers	Tree	Easy
1023	Camelcase Matching	Trie,String	Medium
1024	Video Stitching	Dynamic Programming	Medium
1025	Divisor Game	Math,Dynamic Programming	Easy
1026	Maximum Difference Between Node and Ancestor	Tree,Depth-first Search	Medium
1027	Longest Arithmetic Subsequence	Dynamic Programming	Medium
1028	Recover a Tree From Preorder Traversal	Tree,Depth-first Search	Hard
1029	Two City Scheduling	Greedy	Medium
1030	Matrix Cells in Distance Order	Sort	Easy
1031	Maximum Sum of Two Non-Overlapping Subarrays	Array	Medium
1032	Stream of Characters	Trie	Hard
1033	Moving Stones Until Consecutive	Brainteaser	Easy
1034	Coloring A Border	Depth-first Search	Medium
1035	Uncrossed Lines	Array	Medium
1036	Escape a Large Maze	Breadth-first Search	Hard
1037	Valid Boomerang	Math	Easy
1038	Binary Search Tree to Greater Sum Tree	Tree,Depth-first Search,Binary Search Tree,Recursion	Medium
1039	Minimum Score Triangulation of Polygon	Dynamic Programming	Medium
1040	Moving Stones Until Consecutive II	Array,Sliding Window	Medium
1041	Robot Bounded In Circle	Math	Medium
1042	Flower Planting With No Adjacent	Graph	Medium
1043	Partition Array for Maximum Sum	Dynamic Programming	Medium
1044	Longest Duplicate Substring	Hash Table,Binary Search	Hard
1045	Customers Who Bought All Products		Medium	🔒
1046	Last Stone Weight	Heap,Greedy	Easy
1047	Remove All Adjacent Duplicates In String	Stack	Easy
1048	Longest String Chain	Hash Table,Dynamic Programming	Medium
1049	Last Stone Weight II	Dynamic Programming	Medium
1050	Actors and Directors Who Cooperated At Least Three Times		Easy	🔒
1051	Height Checker	Array	Easy
1052	Grumpy Bookstore Owner	Array,Sliding Window	Medium
1053	Previous Permutation With One Swap	Greedy,Array	Medium
1054	Distant Barcodes	Heap,Sort	Medium
1055	Shortest Way to Form String	Greedy,Dynamic Programming	Medium	🔒
1056	Confusing Number	Math	Easy	🔒
1057	Campus Bikes	Greedy,Sort	Medium	🔒
1058	Minimize Rounding Error to Meet Target	Greedy,Math,Dynamic Programming	Medium	🔒
1059	All Paths from Source Lead to Destination	Depth-first Search,Graph	Medium	🔒
1060	Missing Element in Sorted Array	Binary Search	Medium	🔒
1061	Lexicographically Smallest Equivalent String	Depth-first Search,Union Find	Medium	🔒
1062	Longest Repeating Substring	String	Medium	🔒
1063	Number of Valid Subarrays	Stack	Hard	🔒
1064	Fixed Point	Array,Binary Search	Easy	🔒
1065	Index Pairs of a String	Trie,String	Easy	🔒
1066	Campus Bikes II	Dynamic Programming,Backtracking	Medium	🔒
1067	Digit Count in Range	Math,Dynamic Programming	Hard	🔒
1068	Product Sales Analysis I		Easy	🔒
1069	Product Sales Analysis II		Easy	🔒
1070	Product Sales Analysis III		Medium	🔒
1071	Greatest Common Divisor of Strings	String	Easy
1072	Flip Columns For Maximum Number of Equal Rows	Hash Table	Medium
1073	Adding Two Negabinary Numbers	Math	Medium
1074	Number of Submatrices That Sum to Target	Array,Dynamic Programming,Sliding Window	Hard
1075	Project Employees I		Easy	🔒
1076	Project Employees II		Easy	🔒
1077	Project Employees III		Medium	🔒
1078	Occurrences After Bigram	Hash Table	Easy
1079	Letter Tile Possibilities	Backtracking	Medium
1080	Insufficient Nodes in Root to Leaf Paths	Depth-first Search	Medium
1081	Smallest Subsequence of Distinct Characters	Stack,Greedy,String	Medium
1082	Sales Analysis I		Easy	🔒
1083	Sales Analysis II		Easy	🔒
1084	Sales Analysis III		Easy	🔒
1085	Sum of Digits in the Minimum Number	Array	Easy	🔒
1086	High Five	Sort,Array,Hash Table	Easy	🔒
1087	Brace Expansion	Backtracking	Medium	🔒
1088	Confusing Number II	Math,Backtracking	Hard	🔒
1089	Duplicate Zeros	Array	Easy
1090	Largest Values From Labels	Greedy,Hash Table	Medium
1091	Shortest Path in Binary Matrix	Breadth-first Search	Medium
1092	Shortest Common Supersequence	Dynamic Programming	Hard
1093	Statistics from a Large Sample	Math,Two Pointers	Medium
1094	Car Pooling	Greedy	Medium
1095	Find in Mountain Array	Binary Search	Hard
1096	Brace Expansion II	String	Hard
1097	Game Play Analysis V		Hard	🔒
1098	Unpopular Books		Medium	🔒
1099	Two Sum Less Than K	Sort,Array,Two Pointers	Easy	🔒
1100	Find K-Length Substrings With No Repeated Characters	String,Sliding Window	Medium	🔒
1101	The Earliest Moment When Everyone Become Friends	Union Find	Medium	🔒
1102	Path With Maximum Minimum Value	Depth-first Search,Union Find,Graph	Medium	🔒
1103	Distribute Candies to People	Math	Easy
1104	Path In Zigzag Labelled Binary Tree	Tree,Math	Medium
1105	Filling Bookcase Shelves	Dynamic Programming	Medium
1106	Parsing A Boolean Expression	String	Hard
1107	New Users Daily Count		Medium	🔒
1108	Defanging an IP Address	String	Easy
1109	Corporate Flight Bookings	Array,Math	Medium
1110	Delete Nodes And Return Forest	Tree,Depth-first Search	Medium
1111	Maximum Nesting Depth of Two Valid Parentheses Strings	Greedy,Binary Search	Medium
1112	Highest Grade For Each Student		Medium	🔒
1113	Reported Posts		Easy	🔒
1114	Print in Order		Easy
1115	Print FooBar Alternately		Medium
1116	Print Zero Even Odd		Medium
1117	Building H2O		Medium
1118	Number of Days in a Month		Easy	🔒
1119	Remove Vowels from a String	String	Easy	🔒
1120	Maximum Average Subtree	Tree	Medium	🔒
1121	Divide Array Into Increasing Sequences	Math	Hard	🔒
1122	Relative Sort Array	Sort,Array	Easy
1123	Lowest Common Ancestor of Deepest Leaves	Tree,Depth-first Search	Medium
1124	Longest Well-Performing Interval	Stack	Medium
1125	Smallest Sufficient Team	Bit Manipulation,Dynamic Programming	Hard
1126	Active Businesses		Medium	🔒
1127	User Purchase Platform		Hard	🔒
1128	Number of Equivalent Domino Pairs	Array	Easy
1129	Shortest Path with Alternating Colors	Breadth-first Search,Graph	Medium
1130	Minimum Cost Tree From Leaf Values	Stack,Tree,Dynamic Programming	Medium
1131	Maximum of Absolute Value Expression	Bit Manipulation,Math	Medium
1132	Reported Posts II		Medium	🔒
1133	Largest Unique Number	Array,Hash Table	Easy	🔒
1134	Armstrong Number	Math	Easy	🔒
1135	Connecting Cities With Minimum Cost	Union Find,Graph	Medium	🔒
1136	Parallel Courses	Depth-first Search,Graph,Dynamic Programming	Medium	🔒
1137	N-th Tribonacci Number	Recursion	Easy
1138	Alphabet Board Path	Hash Table,String	Medium
1139	Largest 1-Bordered Square	Dynamic Programming	Medium
1140	Stone Game II	Dynamic Programming	Medium
1141	User Activity for the Past 30 Days I		Easy	🔒
1142	User Activity for the Past 30 Days II		Easy	🔒
1143	Longest Common Subsequence	Dynamic Programming	Medium
1144	Decrease Elements To Make Array Zigzag	Array	Medium
1145	Binary Tree Coloring Game	Tree,Depth-first Search	Medium
1146	Snapshot Array	Array	Medium
1147	Longest Chunked Palindrome Decomposition	Dynamic Programming	Hard
1148	Article Views I		Easy	🔒
1149	Article Views II		Medium	🔒
1150	Check If a Number Is Majority Element in a Sorted Array	Array,Binary Search	Easy	🔒
1151	Minimum Swaps to Group All 1's Together	Array,Sliding Window	Medium	🔒
1152	Analyze User Website Visit Pattern	Sort,Array,Hash Table	Medium	🔒
1153	String Transforms Into Another String	Graph	Hard	🔒
1154	Day of the Year	Math	Easy
1155	Number of Dice Rolls With Target Sum	Dynamic Programming	Medium
1156	Swap For Longest Repeated Character Substring	String	Medium
1157	Online Majority Element In Subarray	Segment Tree,Array,Binary Search	Hard
1158	Market Analysis I		Medium	🔒
1159	Market Analysis II		Hard	🔒
1160	Find Words That Can Be Formed by Characters	Array,Hash Table	Easy
1161	Maximum Level Sum of a Binary Tree	Tree,Breadth-first Search	Medium
1162	As Far from Land as Possible	Breadth-first Search,Graph	Medium
1163	Last Substring in Lexicographical Order	String	Hard
1164	Product Price at a Given Date		Medium	🔒
1165	Single-Row Keyboard	String	Easy	🔒
1166	Design File System	Design,Hash Table	Medium	🔒
1167	Minimum Cost to Connect Sticks	Greedy	Medium	🔒
1168	Optimize Water Distribution in a Village	Union Find,Graph	Hard	🔒
1169	Invalid Transactions	Array,String	Medium
1170	Compare Strings by Frequency of the Smallest Character	Array,String,Binary Search	Medium
1171	Remove Zero Sum Consecutive Nodes from Linked List	Linked List	Medium
1172	Dinner Plate Stacks	Design	Hard
1173	Immediate Food Delivery I		Easy	🔒
1174	Immediate Food Delivery II		Medium	🔒
1175	Prime Arrangements	Math	Easy
1176	Diet Plan Performance	Array,Sliding Window	Easy	🔒
1177	Can Make Palindrome from Substring	Array,String	Medium
1178	Number of Valid Words for Each Puzzle	Bit Manipulation,Hash Table	Hard
1179	Reformat Department Table		Easy
1180	Count Substrings with Only One Distinct Letter	Math,String	Easy	🔒
1181	Before and After Puzzle	String	Medium	🔒
1182	Shortest Distance to Target Color	Binary Search	Medium	🔒
1183	Maximum Number of Ones	Sort,Math	Hard	🔒
1184	Distance Between Bus Stops	Array	Easy
1185	Day of the Week	Array	Easy
1186	Maximum Subarray Sum with One Deletion	Dynamic Programming	Medium
1187	Make Array Strictly Increasing	Dynamic Programming	Hard
1188	Design Bounded Blocking Queue		Medium	🔒
1189	Maximum Number of Balloons	Hash Table,String	Easy
1190	Reverse Substrings Between Each Pair of Parentheses	Stack	Medium
1191	K-Concatenation Maximum Sum	Dynamic Programming	Medium
1192	Critical Connections in a Network	Depth-first Search	Hard
1193	Monthly Transactions I		Medium	🔒
1194	Tournament Winners		Hard	🔒
1195	Fizz Buzz Multithreaded		Medium
1196	How Many Apples Can You Put into the Basket	Greedy	Easy	🔒
1197	Minimum Knight Moves	Breadth-first Search	Medium	🔒
1198	Find Smallest Common Element in All Rows	Hash Table,Binary Search	Medium	🔒
1199	Minimum Time to Build Blocks	Math,Dynamic Programming	Hard	🔒
1200	Minimum Absolute Difference	Array	Easy
1201	Ugly Number III	Math,Binary Search	Medium
1202	Smallest String With Swaps	Union Find,Array	Medium
1203	Sort Items by Groups Respecting Dependencies	Depth-first Search,Graph,Topological Sort	Hard
1204	Last Person to Fit in the Elevator		Medium	🔒
1205	Monthly Transactions II		Medium	🔒
1206	Design Skiplist	Design	Hard
1207	Unique Number of Occurrences	Hash Table	Easy
1208	Get Equal Substrings Within Budget	Array,Sliding Window	Medium
1209	Remove All Adjacent Duplicates in String II	Stack	Medium
1210	Minimum Moves to Reach Target with Rotations	Breadth-first Search	Hard
1211	Queries Quality and Percentage		Easy	🔒
1212	Team Scores in Football Tournament		Medium	🔒
1213	Intersection of Three Sorted Arrays	Hash Table,Two Pointers	Easy	🔒
1214	Two Sum BSTs	Binary Search Tree	Medium	🔒
1215	Stepping Numbers	Backtracking	Medium	🔒
1216	Valid Palindrome III	String,Dynamic Programming	Hard	🔒
1217	Minimum Cost to Move Chips to The Same Position	Greedy,Array,Math	Easy
1218	Longest Arithmetic Subsequence of Given Difference	Hash Table,Math,Dynamic Programming	Medium
1219	Path with Maximum Gold	Backtracking	Medium
1220	Count Vowels Permutation	Dynamic Programming	Hard
1221	Split a String in Balanced Strings	Greedy,String	Easy
1222	Queens That Can Attack the King	Array	Medium
1223	Dice Roll Simulation	Dynamic Programming	Medium
1224	Maximum Equal Frequency	Hash Table	Hard
1225	Report Contiguous Dates		Hard	🔒
1226	The Dining Philosophers		Medium
1227	Airplane Seat Assignment Probability	Brainteaser,Math,Dynamic Programming	Medium
1228	Missing Number In Arithmetic Progression	Math	Easy	🔒
1229	Meeting Scheduler	Sort,Two Pointers,Line Sweep	Medium	🔒
1230	Toss Strange Coins	Math,Dynamic Programming	Medium	🔒
1231	Divide Chocolate	Greedy,Binary Search	Hard	🔒
1232	Check If It Is a Straight Line	Geometry,Array,Math	Easy
1233	Remove Sub-Folders from the Filesystem	Array,String	Medium
1234	Replace the Substring for Balanced String	Two Pointers,String	Medium
1235	Maximum Profit in Job Scheduling	Sort,Binary Search,Dynamic Programming	Hard
1236	Web Crawler	Depth-first Search,Breadth-first Search	Medium	🔒
1237	Find Positive Integer Solution for a Given Equation	Math,Binary Search	Medium
1238	Circular Permutation in Binary Representation	Math	Medium
1239	Maximum Length of a Concatenated String with Unique Characters	Bit Manipulation,Backtracking	Medium
1240	Tiling a Rectangle with the Fewest Squares	Dynamic Programming,Backtracking	Hard
1241	Number of Comments per Post		Easy	🔒
1242	Web Crawler Multithreaded	Depth-first Search,Breadth-first Search	Medium	🔒
1243	Array Transformation	Array	Easy	🔒
1244	Design A Leaderboard	Sort,Design,Hash Table	Medium	🔒
1245	Tree Diameter	Tree,Depth-first Search,Breadth-first Search	Medium	🔒
1246	Palindrome Removal	Dynamic Programming	Hard	🔒
1247	Minimum Swaps to Make Strings Equal	Greedy,String	Medium
1248	Count Number of Nice Subarrays	Two Pointers	Medium
1249	Minimum Remove to Make Valid Parentheses	Stack,String	Medium
1250	Check If It Is a Good Array	Math	Hard
1251	Average Selling Price		Easy	🔒
1252	Cells with Odd Values in a Matrix	Array	Easy
1253	Reconstruct a 2-Row Binary Matrix	Greedy,Math	Medium
1254	Number of Closed Islands	Depth-first Search	Medium
1255	Maximum Score Words Formed by Letters	Bit Manipulation	Hard
1256	Encode Number	Bit Manipulation,Math	Medium	🔒
1257	Smallest Common Region	Tree	Medium	🔒
1258	Synonymous Sentences	Backtracking	Medium	🔒
1259	Handshakes That Don't Cross	Math,Dynamic Programming	Hard	🔒
1260	Shift 2D Grid	Array	Easy
1261	Find Elements in a Contaminated Binary Tree	Tree,Hash Table	Medium
1262	Greatest Sum Divisible by Three	Dynamic Programming	Medium
1263	Minimum Moves to Move a Box to Their Target Location	Breadth-first Search	Hard
1264	Page Recommendations		Medium	🔒
1265	Print Immutable Linked List in Reverse		Medium	🔒
1266	Minimum Time Visiting All Points	Geometry,Array	Easy
1267	Count Servers that Communicate	Graph,Array	Medium
1268	Search Suggestions System	String	Medium
1269	Number of Ways to Stay in the Same Place After Some Steps	Dynamic Programming	Hard
1270	All People Report to the Given Manager		Medium	🔒
1271	Hexspeak	Math,String	Easy	🔒
1272	Remove Interval	Math,Line Sweep	Medium	🔒
1273	Delete Tree Nodes	Depth-first Search,Dynamic Programming	Medium	🔒
1274	Number of Ships in a Rectangle	Divide and Conquer	Hard	🔒
1275	Find Winner on a Tic Tac Toe Game	Array	Easy
1276	Number of Burgers with No Waste of Ingredients	Greedy,Math	Medium
1277	Count Square Submatrices with All Ones	Array,Dynamic Programming	Medium
1278	Palindrome Partitioning III	Dynamic Programming	Hard
1279	Traffic Light Controlled Intersection		Easy	🔒
1280	Students and Examinations		Easy	🔒
1281	Subtract the Product and Sum of Digits of an Integer	Math	Easy
1282	Group the People Given the Group Size They Belong To	Greedy	Medium
1283	Find the Smallest Divisor Given a Threshold	Binary Search	Medium
1284	Minimum Number of Flips to Convert Binary Matrix to Zero Matrix	Breadth-first Search	Hard
1285	Find the Start and End Number of Continuous Ranges		Medium	🔒
1286	Iterator for Combination	Design,Backtracking	Medium
1287	Element Appearing More Than 25% In Sorted Array	Array	Easy
1288	Remove Covered Intervals	Greedy,Sort,Line Sweep	Medium
1289	Minimum Falling Path Sum II	Dynamic Programming	Hard
1290	Convert Binary Number in a Linked List to Integer	Bit Manipulation,Linked List	Easy
1291	Sequential Digits	Backtracking	Medium
1292	Maximum Side Length of a Square with Sum Less than or Equal to Threshold	Array,Binary Search	Medium
1293	Shortest Path in a Grid with Obstacles Elimination	Breadth-first Search	Hard
1294	Weather Type in Each Country		Easy	🔒
1295	Find Numbers with Even Number of Digits	Array	Easy
1296	Divide Array in Sets of K Consecutive Numbers	Greedy,Array	Medium
1297	Maximum Number of Occurrences of a Substring	Bit Manipulation,String	Medium
1298	Maximum Candies You Can Get from Boxes	Breadth-first Search	Hard
1299	Replace Elements with Greatest Element on Right Side	Array	Easy
1300	Sum of Mutated Array Closest to Target	Array,Binary Search	Medium
1301	Number of Paths with Max Score	Dynamic Programming	Hard
1302	Deepest Leaves Sum	Tree,Depth-first Search	Medium
1303	Find the Team Size		Easy	🔒
1304	Find N Unique Integers Sum up to Zero	Array	Easy
1305	All Elements in Two Binary Search Trees	Sort,Tree	Medium
1306	Jump Game III	Depth-first Search,Breadth-first Search,Recursion	Medium
1307	Verbal Arithmetic Puzzle	Math,Backtracking	Hard
1308	Running Total for Different Genders		Medium	🔒
1309	Decrypt String from Alphabet to Integer Mapping	String	Easy
1310	XOR Queries of a Subarray	Bit Manipulation	Medium
1311	Get Watched Videos by Your Friends	Breadth-first Search,Hash Table,String	Medium
1312	Minimum Insertion Steps to Make a String Palindrome	Dynamic Programming	Hard
1313	Decompress Run-Length Encoded List	Array	Easy
1314	Matrix Block Sum	Dynamic Programming	Medium
1315	Sum of Nodes with Even-Valued Grandparent	Tree,Depth-first Search	Medium
1316	Distinct Echo Substrings	String	Hard
1317	Convert Integer to the Sum of Two No-Zero Integers	Math	Easy
1318	Minimum Flips to Make a OR b Equal to c	Bit Manipulation	Medium
1319	Number of Operations to Make Network Connected	Depth-first Search,Breadth-first Search,Union Find	Medium
1320	Minimum Distance to Type a Word Using Two Fingers	Dynamic Programming	Hard
1321	Restaurant Growth		Medium	🔒
1322	Ads Performance		Easy	🔒
1323	Maximum 69 Number	Math	Easy
1324	Print Words Vertically	String	Medium
1325	Delete Leaves With a Given Value	Tree	Medium
1326	Minimum Number of Taps to Open to Water a Garden	Greedy,Dynamic Programming	Hard
1327	List the Products Ordered in a Period		Easy	🔒
1328	Break a Palindrome	String	Medium
1329	Sort the Matrix Diagonally	Sort,Array	Medium
1330	Reverse Subarray To Maximize Array Value	Array,Math	Hard
1331	Rank Transform of an Array	Array	Easy
1332	Remove Palindromic Subsequences	String	Easy
1333	Filter Restaurants by Vegan-Friendly, Price and Distance	Sort,Array	Medium
1334	Find the City With the Smallest Number of Neighbors at a Threshold Distance	Graph	Medium
1335	Minimum Difficulty of a Job Schedule	Dynamic Programming	Hard
1336	Number of Transactions per Visit		Hard	🔒
1337	The K Weakest Rows in a Matrix	Array,Binary Search	Easy
1338	Reduce Array Size to The Half	Greedy,Array	Medium
1339	Maximum Product of Splitted Binary Tree	Tree,Dynamic Programming	Medium
1340	Jump Game V	Dynamic Programming	Hard
1341	Movie Rating		Medium	🔒
1342	Number of Steps to Reduce a Number to Zero	Bit Manipulation	Easy
1343	Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold	Array	Medium
1344	Angle Between Hands of a Clock	Math	Medium
1345	Jump Game IV	Breadth-first Search	Hard
1346	Check If N and Its Double Exist	Array	Easy
1347	Minimum Number of Steps to Make Two Strings Anagram	String	Medium
1348	Tweet Counts Per Frequency	Design	Medium
1349	Maximum Students Taking Exam	Dynamic Programming	Hard
1350	Students With Invalid Departments		Easy	🔒
1351	Count Negative Numbers in a Sorted Matrix	Array,Binary Search	Easy
1352	Product of the Last K Numbers	Design,Array	Medium
1353	Maximum Number of Events That Can Be Attended	Greedy,Sort,Segment Tree	Medium
1354	Construct Target Array With Multiple Sums	Greedy	Hard
1355	Activity Participants		Medium	🔒
1356	Sort Integers by The Number of 1 Bits	Sort,Bit Manipulation	Easy
1357	Apply Discount Every n Orders	Design	Medium
1358	Number of Substrings Containing All Three Characters	String	Medium
1359	Count All Valid Pickup and Delivery Options	Math,Dynamic Programming	Hard
1360	Number of Days Between Two Dates		Easy
1361	Validate Binary Tree Nodes	Graph	Medium
1362	Closest Divisors	Math	Medium
1363	Largest Multiple of Three	Math,Dynamic Programming	Hard
1364	Number of Trusted Contacts of a Customer		Medium	🔒
1365	How Many Numbers Are Smaller Than the Current Number	Array,Hash Table	Easy
1366	Rank Teams by Votes	Sort,Array	Medium
1367	Linked List in Binary Tree	Tree,Linked List,Dynamic Programming	Medium
1368	Minimum Cost to Make at Least One Valid Path in a Grid	Breadth-first Search	Hard
1369	Get the Second Most Recent Activity		Hard	🔒
1370	Increasing Decreasing String	Sort,String	Easy
1371	Find the Longest Substring Containing Vowels in Even Counts	String	Medium
1372	Longest ZigZag Path in a Binary Tree	Tree,Dynamic Programming	Medium
1373	Maximum Sum BST in Binary Tree	Binary Search Tree,Dynamic Programming	Hard
1374	Generate a String With Characters That Have Odd Counts	String	Easy
1375	Bulb Switcher III	Array	Medium
1376	Time Needed to Inform All Employees	Depth-first Search	Medium
1377	Frog Position After T Seconds	Depth-first Search	Hard
1378	Replace Employee ID With The Unique Identifier		Easy	🔒
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Tree,Depth-first Search,Breadth-first Search,Recursion	Medium
1380	Lucky Numbers in a Matrix	Array	Easy
1381	Design a Stack With Increment Operation	Stack,Design	Medium
1382	Balance a Binary Search Tree	Binary Search Tree	Medium
1383	Maximum Performance of a Team	Greedy,Sort	Hard
1384	Total Sales Amount by Year		Hard	🔒
1385	Find the Distance Value Between Two Arrays	Array	Easy
1386	Cinema Seat Allocation	Greedy,Array	Medium
1387	Sort Integers by The Power Value	Sort,Graph	Medium
1388	Pizza With 3n Slices	Dynamic Programming	Hard
1389	Create Target Array in the Given Order	Array	Easy
1390	Four Divisors	Math	Medium
1391	Check if There is a Valid Path in a Grid	Depth-first Search,Breadth-first Search	Medium
1392	Longest Happy Prefix	String	Hard
1393	Capital GainLoss		Medium	🔒
1394	Find Lucky Integer in an Array	Array	Easy
1395	Count Number of Teams	Array	Medium
1396	Design Underground System	Design	Medium
1397	Find All Good Strings	Dynamic Programming	Hard
1398	Customers Who Bought Products A and B but Not C		Medium	🔒
1399	Count Largest Group	Array	Easy
1400	Construct K Palindrome Strings	Greedy	Medium
1401	Circle and Rectangle Overlapping	Geometry	Medium
1402	Reducing Dishes	Dynamic Programming	Hard
1403	Minimum Subsequence in Non-Increasing Order	Greedy,Sort	Easy
1404	Number of Steps to Reduce a Number in Binary Representation to One	Bit Manipulation,String	Medium
1405	Longest Happy String	Greedy,Dynamic Programming	Medium
1406	Stone Game III	Dynamic Programming	Hard
1407	Top Travellers		Easy	🔒
1408	String Matching in an Array	String	Easy
1409	Queries on a Permutation With Key	Array	Medium
1410	HTML Entity Parser	Stack,String	Medium
1411	Number of Ways to Paint N × 3 Grid	Dynamic Programming	Hard
1412	Find the Quiet Students in All Exams		Hard	🔒
1413	Minimum Value to Get Positive Step by Step Sum	Array	Easy
1414	Find the Minimum Number of Fibonacci Numbers Whose Sum Is K	Greedy,Array	Medium
1415	The k-th Lexicographical String of All Happy Strings of Length n	Backtracking	Medium
1416	Restore The Array	Dynamic Programming	Hard
1417	Reformat The String	String	Easy
1418	Display Table of Food Orders in a Restaurant	Hash Table	Medium
1419	Minimum Number of Frogs Croaking	String	Medium
1420	Build Array Where You Can Find The Maximum Exactly K Comparisons	Dynamic Programming	Hard
1421	NPV Queries		Medium	🔒
1422	Maximum Score After Splitting a String	String	Easy
1423	Maximum Points You Can Obtain from Cards	Array,Dynamic Programming,Sliding Window	Medium
1424	Diagonal Traverse II	Sort,Array	Medium
1425	Constrained Subsequence Sum	Dynamic Programming	Hard
1426	Counting Elements	Array	Easy	🔒
1427	Perform String Shifts	Array,Math	Easy	🔒
1428	Leftmost Column with at Least a One	Array	Medium	🔒
1429	First Unique Number	Design,Hash Table	Medium	🔒
1430	Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree	Tree	Medium	🔒
1431	Kids With the Greatest Number of Candies	Array	Easy
1432	Max Difference You Can Get From Changing an Integer	String	Medium
1433	Check If a String Can Break Another String	Greedy,String	Medium
1434	Number of Ways to Wear Different Hats to Each Other	Bit Manipulation,Dynamic Programming	Hard
1435	Create a Session Bar Chart		Easy	🔒
1436	Destination City	String	Easy
1437	Check If All 1's Are at Least Length K Places Away	Array	Easy
1438	Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit	Array,Sliding Window	Medium
1439	Find the Kth Smallest Sum of a Matrix With Sorted Rows	Heap	Hard
1440	Evaluate Boolean Expression		Medium	🔒
1441	Build an Array With Stack Operations	Stack	Easy
1442	Count Triplets That Can Form Two Arrays of Equal XOR	Bit Manipulation,Array,Math	Medium
1443	Minimum Time to Collect All Apples in a Tree	Tree,Depth-first Search	Medium
1444	Number of Ways of Cutting a Pizza	Dynamic Programming	Hard
1445	Apples & Oranges		Medium	🔒
1446	Consecutive Characters	String	Easy
1447	Simplified Fractions	Math	Medium
1448	Count Good Nodes in Binary Tree	Tree,Depth-first Search	Medium
1449	Form Largest Integer With Digits That Add up to Target	String,Dynamic Programming	Hard
1450	Number of Students Doing Homework at a Given Time	Array	Easy
1451	Rearrange Words in a Sentence	Sort,String	Medium
1452	People Whose List of Favorite Companies Is Not a Subset of Another List	Sort,String	Medium
1453	Maximum Number of Darts Inside of a Circular Dartboard	Geometry	Hard
1454	Active Users		Medium	🔒
1455	Check If a Word Occurs As a Prefix of Any Word in a Sentence	String	Easy
1456	Maximum Number of Vowels in a Substring of Given Length	String,Sliding Window	Medium
1457	Pseudo-Palindromic Paths in a Binary Tree	Bit Manipulation,Tree,Depth-first Search	Medium
1458	Max Dot Product of Two Subsequences	Dynamic Programming	Hard
1459	Rectangles Area		Medium	🔒
1460	Make Two Arrays Equal by Reversing Sub-arrays	Array	Easy
1461	Check If a String Contains All Binary Codes of Size K	Bit Manipulation,String	Medium
1462	Course Schedule IV	Graph	Medium
1463	Cherry Pickup II	Dynamic Programming	Hard
1464	Maximum Product of Two Elements in an Array	Array	Easy
1465	Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts	Array	Medium
1466	Reorder Routes to Make All Paths Lead to the City Zero	Tree,Depth-first Search	Medium
1467	Probability of a Two Boxes Having The Same Number of Distinct Balls	Math,Backtracking	Hard
1468	Calculate Salaries		Medium	🔒
1469	Find All The Lonely Nodes	Tree,Depth-first Search	Easy	🔒
1470	Shuffle the Array	Array	Easy
1471	The k Strongest Values in an Array	Sort,Array	Medium
1472	Design Browser History	Design	Medium
1473	Paint House III	Dynamic Programming	Hard
1474	Delete N Nodes After M Nodes of a Linked List	Linked List	Easy	🔒
1475	Final Prices With a Special Discount in a Shop	Array	Easy
1476	Subrectangle Queries	Array	Medium
1477	Find Two Non-overlapping Sub-arrays Each With Target Sum	Dynamic Programming	Medium
1478	Allocate Mailboxes	Math,Dynamic Programming	Hard
1479	Sales by Day of the Week		Hard	🔒
1480	Running Sum of 1d Array	Array	Easy
1481	Least Number of Unique Integers after K Removals	Sort,Array	Medium
1482	Minimum Number of Days to Make m Bouquets	Array,Binary Search	Medium
1483	Kth Ancestor of a Tree Node	Dynamic Programming	Hard
1484	Group Sold Products By The Date		Easy	🔒
1485	Clone Binary Tree With Random Pointer	Tree,Depth-first Search	Medium	🔒
1486	XOR Operation in an Array	Bit Manipulation,Array	Easy
1487	Making File Names Unique	Hash Table,String	Medium
1488	Avoid Flood in The City	Array,Hash Table	Medium
1489	Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree	Depth-first Search,Union Find	Hard
1490	Clone N-ary Tree	Tree,Depth-first Search,Breadth-first Search,Hash Table	Medium	🔒
1491	Average Salary Excluding the Minimum and Maximum Salary	Sort,Array	Easy
1492	The kth Factor of n	Math	Medium
1493	Longest Subarray of 1's After Deleting One Element	Array	Medium
1494	Parallel Courses II	Graph	Hard
1495	Friendly Movies Streamed Last Month		Easy	🔒
1496	Path Crossing	String	Easy
1497	Check If Array Pairs Are Divisible by k	Greedy,Array,Math	Medium
1498	Number of Subsequences That Satisfy the Given Sum Condition	Sort,Sliding Window	Medium
1499	Max Value of Equation	Array,Sliding Window	Hard
1500	Design a File Sharing System	Design,Array	Medium	🔒
1501	Countries You Can Safely Invest In		Medium	🔒
1502	Can Make Arithmetic Progression From Sequence	Sort,Array	Easy
1503	Last Moment Before All Ants Fall Out of a Plank	Brainteaser,Array	Medium
1504	Count Submatrices With All Ones	Dynamic Programming	Medium
1505	Minimum Possible Integer After at Most K Adjacent Swaps On Digits	Greedy	Hard
1506	Find Root of N-Ary Tree		Medium	🔒
1507	Reformat Date	String	Easy
1508	Range Sum of Sorted Subarray Sums	Sort,Array	Medium
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	Sort,Array	Medium
1510	Stone Game IV	Dynamic Programming	Hard
1511	Customer Order Frequency		Easy	🔒
1512	Number of Good Pairs	Array,Hash Table,Math	Easy
1513	Number of Substrings With Only 1s	Math,String	Medium
1514	Path with Maximum Probability	Graph	Medium
1515	Best Position for a Service Centre	Geometry	Hard
1516	Move Sub-Tree of N-Ary Tree	Tree	Hard	🔒
1517	Find Users With Valid E-Mails		Easy	🔒
1518	Water Bottles	Greedy	Easy
1519	Number of Nodes in the Sub-Tree With the Same Label	Depth-first Search,Breadth-first Search	Medium
1520	Maximum Number of Non-Overlapping Substrings	Greedy	Hard
1521	Find a Value of a Mysterious Function Closest to Target	Bit Manipulation,Segment Tree,Binary Search	Hard
1522	Diameter of N-Ary Tree		Medium	🔒
1523	Count Odd Numbers in an Interval Range	Math	Easy
1524	Number of Sub-arrays With Odd Sum	Array,Math	Medium
1525	Number of Good Ways to Split a String	Bit Manipulation,String	Medium
1526	Minimum Number of Increments on Subarrays to Form a Target Array	Segment Tree	Hard
1527	Patients With a Condition		Easy	🔒
1528	Shuffle String	Sort	Easy
1529	Bulb Switcher IV	String	Medium
1530	Number of Good Leaf Nodes Pairs	Tree,Depth-first Search	Medium
1531	String Compression II	String,Dynamic Programming	Hard
1532	The Most Recent Three Orders		Medium	🔒
1533	Find the Index of the Large Integer	Binary Search	Medium	🔒
1534	Count Good Triplets	Array	Easy
1535	Find the Winner of an Array Game	Array	Medium
1536	Minimum Swaps to Arrange a Binary Grid	Greedy	Medium
1537	Get the Maximum Score	Dynamic Programming	Hard
1538	Guess the Majority in a Hidden Array		Medium	🔒
1539	Kth Missing Positive Number	Array,Hash Table	Easy
1540	Can Convert String in K Moves	Greedy,String	Medium
1541	Minimum Insertions to Balance a Parentheses String	Stack,String	Medium
1542	Find Longest Awesome Substring	Bit Manipulation,String	Hard
1543	Fix Product Name Format		Easy	🔒
1544	Make The String Great	Stack,String	Easy
1545	Find Kth Bit in Nth Binary String	String	Medium
1546	Maximum Number of Non-Overlapping Subarrays With Sum Equals Target	Dynamic Programming	Medium
1547	Minimum Cost to Cut a Stick	Dynamic Programming	Hard
1548	The Most Similar Path in a Graph	Graph,Dynamic Programming	Hard	🔒
1549	The Most Recent Orders for Each Product		Medium	🔒
1550	Three Consecutive Odds	Array	Easy
1551	Minimum Operations to Make Array Equal	Math	Medium
1552	Magnetic Force Between Two Balls	Array,Binary Search	Medium
1553	Minimum Number of Days to Eat N Oranges	Dynamic Programming	Hard
1554	Strings Differ by One Character		Medium	🔒
1555	Bank Account Summary		Medium	🔒
1556	Thousand Separator	String	Easy
1557	Minimum Number of Vertices to Reach All Nodes	Graph	Medium
1558	Minimum Numbers of Function Calls to Make Target Array	Greedy	Medium
1559	Detect Cycles in 2D Grid	Depth-first Search	Hard
1560	Most Visited Sector in a Circular Track	Array	Easy
1561	Maximum Number of Coins You Can Get	Sort	Medium
1562	Find Latest Group of Size M	Binary Search	Medium
1563	Stone Game V	Dynamic Programming	Hard
1564	Put Boxes Into the Warehouse I	Greedy	Medium	🔒
1565	Unique Orders and Customers Per Month		Easy	🔒
1566	Detect Pattern of Length M Repeated K or More Times	Array	Easy
1567	Maximum Length of Subarray With Positive Product	Greedy	Medium
1568	Minimum Number of Days to Disconnect Island	Greedy	Hard
1569	Number of Ways to Reorder Array to Get Same BST	Dynamic Programming	Hard
1570	Dot Product of Two Sparse Vectors	Array,Hash Table,Two Pointers	Medium	🔒
1571	Warehouse Manager		Easy	🔒
1572	Matrix Diagonal Sum	Array	Easy
1573	Number of Ways to Split a String	String	Medium
1574	Shortest Subarray to be Removed to Make Array Sorted	Array,Binary Search	Medium
1575	Count All Possible Routes	Dynamic Programming	Hard
1576	Replace All 's to Avoid Consecutive Repeating Characters	String	Easy
1577	Number of Ways Where Square of Number Is Equal to Product of Two Numbers	Hash Table,Math	Medium
1578	Minimum Deletion Cost to Avoid Repeating Letters	Greedy	Medium
1579	Remove Max Number of Edges to Keep Graph Fully Traversable	Union Find	Hard
1580	Put Boxes Into the Warehouse II	Greedy	Medium	🔒
1581	Customer Who Visited but Did Not Make Any Transactions		Easy	🔒
1582	Special Positions in a Binary Matrix	Array	Easy
1583	Count Unhappy Friends	Array	Medium
1584	Min Cost to Connect All Points	Union Find	Medium
1585	Check If String Is Transformable With Substring Sort Operations	Greedy,String	Hard
1586	Binary Search Tree Iterator II	Tree,Design	Medium	🔒
1587	Bank Account Summary II		Easy	🔒
1588	Sum of All Odd Length Subarrays	Array	Easy
1589	Maximum Sum Obtained of Any Permutation	Greedy	Medium
1590	Make Sum Divisible by P	Array,Hash Table,Math,Binary Search	Medium
1591	Strange Printer II	Greedy	Hard
1592	Rearrange Spaces Between Words	String	Easy
1593	Split a String Into the Max Number of Unique Substrings	Backtracking	Medium
1594	Maximum Non Negative Product in a Matrix	Greedy,Dynamic Programming	Medium
1595	Minimum Cost to Connect Two Groups of Points	Graph,Dynamic Programming	Hard
1596	The Most Frequently Ordered Products for Each Customer		Medium	🔒
1597	Build Binary Expression Tree From Infix Expression	Tree,String	Hard	🔒
1598	Crawler Log Folder	Stack	Easy
1599	Maximum Profit of Operating a Centennial Wheel	Greedy	Medium
1600	Throne Inheritance	Tree,Design	Medium
1601	Maximum Number of Achievable Transfer Requests	Dynamic Programming	Hard
1602	Find Nearest Right Node in Binary Tree	Tree,Breadth-first Search	Medium	🔒
1603	Design Parking System	Design	Easy
1604	Alert Using Same Key-Card Three or More Times in a One Hour Period	String,Ordered Map	Medium
1605	Find Valid Matrix Given Row and Column Sums	Greedy	Medium
1606	Find Servers That Handled Most Number of Requests	Ordered Map	Hard
1607	Sellers With No Sales		Easy	🔒
1608	Special Array With X Elements Greater Than or Equal X	Array	Easy
1609	Even Odd Tree	Tree	Medium
1610	Maximum Number of Visible Points	Geometry,Two Pointers	Hard
1611	Minimum One Bit Operations to Make Integers Zero	Bit Manipulation,Dynamic Programming	Hard
1612	Check If Two Expression Trees are Equivalent	Tree,Hash Table	Medium	🔒
1613	Find the Missing IDs		Medium	🔒
1614	Maximum Nesting Depth of the Parentheses	String	Easy
1615	Maximal Network Rank	Graph	Medium
1616	Split Two Strings to Make Palindrome	Greedy,Two Pointers,String	Medium
1617	Count Subtrees With Max Distance Between Cities	Backtracking	Hard
1618	Maximum Font to Fit a Sentence in a Screen	String,Binary Search	Medium	🔒
1619	Mean of Array After Removing Some Elements	Array	Easy
1620	Coordinate With Maximum Network Quality	Greedy	Medium
1621	Number of Sets of K Non-Overlapping Line Segments	Dynamic Programming	Medium
1622	Fancy Sequence	Design,Math	Hard
1623	All Valid Triplets That Can Represent a Country		Easy	🔒
1624	Largest Substring Between Two Equal Characters	String	Easy
1625	Lexicographically Smallest String After Applying Operations	Depth-first Search,Breadth-first Search	Medium
1626	Best Team With No Conflicts	Dynamic Programming	Medium
1627	Graph Connectivity With Threshold	Union Find,Math	Hard
1628	Design an Expression Tree With Evaluate Function	Tree,Design	Medium	🔒
1629	Slowest Key	Array	Easy
1630	Arithmetic Subarrays	Sort	Medium
1631	Path With Minimum Effort	Depth-first Search,Union Find,Graph,Binary Search	Medium
1632	Rank Transform of a Matrix	Greedy,Union Find	Hard
1633	Percentage of Users Attended a Contest		Easy	🔒
1634	Add Two Polynomials Represented as Linked Lists	Linked List	Medium	🔒
1635	Hopper Company Queries I		Hard	🔒
1636	Sort Array by Increasing Frequency	Sort,Array	Easy
1637	Widest Vertical Area Between Two Points Containing No Points	Sort	Medium
1638	Count Substrings That Differ by One Character	Trie,Hash Table,String	Medium
1639	Number of Ways to Form a Target String Given a Dictionary	Dynamic Programming	Hard
1640	Check Array Formation Through Concatenation	Sort,Array,Hash Table	Easy
1641	Count Sorted Vowel Strings	Math,Dynamic Programming,Backtracking	Medium
1642	Furthest Building You Can Reach	Heap,Binary Search	Medium
1643	Kth Smallest Instructions	Dynamic Programming	Hard
1644	Lowest Common Ancestor of a Binary Tree II	Tree	Medium	🔒
1645	Hopper Company Queries II		Hard	🔒
1646	Get Maximum in Generated Array	Array	Easy
1647	Minimum Deletions to Make Character Frequencies Unique	Greedy,Sort	Medium
1648	Sell Diminishing-Valued Colored Balls	Greedy,Sort,Math	Medium
1649	Create Sorted Array through Instructions	Binary Indexed Tree,Segment Tree,Binary Search,Ordered Map	Hard
1650	Lowest Common Ancestor of a Binary Tree III	Tree	Medium	🔒
1651	Hopper Company Queries III		Hard	🔒
1652	Defuse the Bomb	Array	Easy
1653	Minimum Deletions to Make String Balanced	Greedy,String	Medium
1654	Minimum Jumps to Reach Home	Breadth-first Search,Dynamic Programming	Medium
1655	Distribute Repeating Integers	Dynamic Programming,Backtracking	Hard
1656	Design an Ordered Stream	Design,Array	Easy
1657	Determine if Two Strings Are Close	Greedy	Medium
1658	Minimum Operations to Reduce X to Zero	Greedy,Two Pointers,Binary Search,Sliding Window	Medium
1659	Maximize Grid Happiness	Dynamic Programming,Backtracking	Hard
1660	Correct a Binary Tree	Tree	Medium	🔒
1661	Average Time of Process per Machine		Easy	🔒
1662	Check If Two String Arrays are Equivalent	String	Easy
1663	Smallest String With A Given Numeric Value	Greedy	Medium
1664	Ways to Make a Fair Array	Greedy,Dynamic Programming	Medium
1665	Minimum Initial Energy to Finish Tasks	Greedy	Hard
1666	Change the Root of a Binary Tree	Tree,Depth-first Search	Medium	🔒
1667	Fix Names in a Table		Easy	🔒
1668	Maximum Repeating Substring	String	Easy
1669	Merge In Between Linked Lists	Linked List	Medium
1670	Design Front Middle Back Queue	Design,Linked List	Medium
1671	Minimum Number of Removals to Make Mountain Array	Dynamic Programming	Hard
1672	Richest Customer Wealth	Array	Easy
1673	Find the Most Competitive Subsequence	Stack,Heap,Greedy,Queue	Medium
1674	Minimum Moves to Make Array Complementary	Greedy	Medium
1675	Minimize Deviation in Array	Heap,Ordered Map	Hard
1676	Lowest Common Ancestor of a Binary Tree IV	Tree,Depth-first Search	Medium	🔒
1677	Product's Worth Over Invoices		Easy	🔒
1678	Goal Parser Interpretation	String	Easy
1679	Max Number of K-Sum Pairs	Hash Table	Medium
1680	Concatenation of Consecutive Binary Numbers	Math	Medium
1681	Minimum Incompatibility	Greedy,Backtracking	Hard
1682	Longest Palindromic Subsequence II	String,Dynamic Programming	Medium	🔒
1683	Invalid Tweets		Easy	🔒
1684	Count the Number of Consistent Strings	String	Easy
1685	Sum of Absolute Differences in a Sorted Array	Greedy,Math	Medium
1686	Stone Game VI	Greedy	Medium
1687	Delivering Boxes from Storage to Ports	Segment Tree,Two Pointers,Dynamic Programming	Hard
1688	Count of Matches in Tournament	Backtracking	Easy
1689	Partitioning Into Minimum Number Of Deci-Binary Numbers	Greedy	Medium
1690	Stone Game VII	Dynamic Programming	Medium
1691	Maximum Height by Stacking Cuboids	Sort,Dynamic Programming	Hard
1692	Count Ways to Distribute Candies	Dynamic Programming	Hard	🔒
1693	Daily Leads and Partners		Easy	🔒
1694	Reformat Phone Number	String	Easy
1695	Maximum Erasure Value	Two Pointers	Medium
1696	Jump Game VI		Medium
1697	Checking Existence of Edge Length Limited Paths	Sort,Union Find	Hard
1698	Number of Distinct Substrings in a String	Trie,String	Medium	🔒
1699	Number of Calls Between Two Persons		Medium	🔒
1700	Number of Students Unable to Eat Lunch	Array	Easy
1701	Average Waiting Time	Array	Medium
1702	Maximum Binary String After Change	Greedy	Medium
1703	Minimum Adjacent Swaps for K Consecutive Ones	Stack	Hard
1704	Determine if String Halves Are Alike	String	Easy
1705	Maximum Number of Eaten Apples	Heap,Greedy	Medium
1706	Where Will the Ball Fall	Dynamic Programming	Medium
1707	Maximum XOR With an Element From Array	Bit Manipulation,Trie	Hard
1708	Largest Subarray Length K	Greedy,Array	Easy	🔒
1709	Biggest Window Between Visits		Medium	🔒
1710	Maximum Units on a Truck	Greedy,Sort	Easy
1711	Count Good Meals	Array,Hash Table,Two Pointers	Medium
1712	Ways to Split Array Into Three Subarrays	Two Pointers,Binary Search	Medium
1713	Minimum Operations to Make a Subsequence	Greedy	Hard
1714	Sum Of Special Evenly-Spaced Elements In Array		Hard	🔒
1715	Count Apples and Oranges		Medium	🔒
1716	Calculate Money in Leetcode Bank	Greedy,Math	Easy
1717	Maximum Score From Removing Substrings	Greedy	Medium
1718	Construct the Lexicographically Largest Valid Sequence	Recursion,Backtracking	Medium
1719	Number Of Ways To Reconstruct A Tree	Tree,Graph	Hard
1720	Decode XORed Array	Bit Manipulation	Easy
1721	Swapping Nodes in a Linked List	Linked List	Medium
1722	Minimize Hamming Distance After Swap Operations	Greedy,Depth-first Search,Union Find	Medium
1723	Find Minimum Time to Finish All Jobs	Recursion,Backtracking	Hard
1724	Checking Existence of Edge Length Limited Paths II	Union Find,Graph,Dynamic Programming	Hard	🔒
1725	Number Of Rectangles That Can Form The Largest Square	Greedy	Easy
1726	Tuple with Same Product	Array,Hash Table	Medium
1727	Largest Submatrix With Rearrangements	Greedy,Sort	Medium
1728	Cat and Mouse II	Dynamic Programming	Hard
1729	Find Followers Count		Easy	🔒
1730	Shortest Path to Get Food	Depth-first Search,Breadth-first Search,Graph	Medium	🔒
1731	The Number of Employees Which Report to Each Employee		Easy	🔒
1732	Find the Highest Altitude	Array	Easy
1733	Minimum Number of People to Teach	Greedy,Array	Medium
1734	Decode XORed Permutation	Bit Manipulation	Medium
1735	Count Ways to Make Array With Product	Math	Hard
1736	Latest Time by Replacing Hidden Digits	Greedy,String	Easy
1737	Change Minimum Characters to Satisfy One of Three Conditions	Greedy,String	Medium
1738	Find Kth Largest XOR Coordinate Value	Array	Medium
1739	Building Boxes	Math,Binary Search	Hard
1740	Find Distance in a Binary Tree	Tree,Depth-first Search,Breadth-first Search	Medium	🔒
1741	Find Total Time Spent by Each Employee		Easy	🔒
1742	Maximum Number of Balls in a Box	Array	Easy
1743	Restore the Array From Adjacent Pairs	Greedy	Medium
1744	Can You Eat Your Favorite Candy on Your Favorite Day	Math	Medium
1745	Palindrome Partitioning IV	String,Dynamic Programming	Hard
1746	Maximum Subarray Sum After One Operation	Dynamic Programming	Medium	🔒
1747	Leetflex Banned Accounts		Medium	🔒
1748	Sum of Unique Elements	Array,Hash Table	Easy
1749	Maximum Absolute Sum of Any Subarray	Greedy	Medium
1750	Minimum Length of String After Deleting Similar Ends	Two Pointers	Medium
1751	Maximum Number of Events That Can Be Attended II	Binary Search,Dynamic Programming	Hard
1752	Check if Array Is Sorted and Rotated	Array	Easy
1753	Maximum Score From Removing Stones	Heap,Math	Medium
1754	Largest Merge Of Two Strings	Greedy	Medium
1755	Closest Subsequence Sum	Divide and Conquer	Hard
1756	Design Most Recently Used Queue	Design,Array	Medium	🔒
1757	Recyclable and Low Fat Products		Easy	🔒
1758	Minimum Changes To Make Alternating Binary String	Greedy,Array	Easy
1759	Count Number of Homogenous Substrings	Greedy,String	Medium
1760	Minimum Limit of Balls in a Bag	Heap,Binary Search	Medium
1761	Minimum Degree of a Connected Trio in a Graph	Graph	Hard
1762	Buildings With an Ocean View	Greedy	Medium	🔒
1763	Longest Nice Substring	String	Easy
1764	Form Array by Concatenating Subarrays of Another Array	Greedy,Array	Medium
1765	Map of Highest Peak	Breadth-first Search,Graph	Medium
1766	Tree of Coprimes	Tree,Depth-first Search,Breadth-first Search,Math	Hard
1767	Find the Subtasks That Did Not Execute		Hard	🔒
1768	Merge Strings Alternately	String	Easy
1769	Minimum Number of Operations to Move All Balls to Each Box	Greedy,Array	Medium
1770	Maximum Score from Performing Multiplication Operations	Dynamic Programming	Medium
1771	Maximize Palindrome Length From Subsequences	Dynamic Programming	Hard
1772	Sort Features by Popularity	Sort,Hash Table	Medium	🔒
1773	Count Items Matching a Rule	Array,String	Easy
1774	Closest Dessert Cost	Greedy	Medium
1775	Equal Sum Arrays With Minimum Number of Operations	Greedy	Medium
1776	Car Fleet II	Math	Hard
1777	Product's Price for Each Store		Easy	🔒
1778	Shortest Path in a Hidden Grid	Depth-first Search,Breadth-first Search,Graph	Medium	🔒
1779	Find Nearest Point That Has the Same X or Y Coordinate	Array	Easy
1780	Check if Number is a Sum of Powers of Three	Recursion,Math,Backtracking	Medium
1781	Sum of Beauty of All Substrings	Hash Table,String	Medium
1782	Count Pairs Of Nodes	Graph	Hard
1783	Grand Slam Titles		Medium	🔒
1784	Check if Binary String Has at Most One Segment of Ones	Greedy	Easy
1785	Minimum Elements to Add to Form a Given Sum	Greedy	Medium
1786	Number of Restricted Paths From First to Last Node	Graph,Dynamic Programming	Medium
1787	Make the XOR of All Segments Equal to Zero	Dynamic Programming	Hard
1788	Maximize the Beauty of the Garden	Greedy	Hard	🔒
1789	Primary Department for Each Employee		Easy	🔒
1790	Check if One String Swap Can Make Strings Equal	String	Easy
1791	Find Center of Star Graph	Graph	Medium
1792	Maximum Average Pass Ratio	Heap	Medium
1793	Maximum Score of a Good Subarray	Greedy	Hard
1794	Count Pairs of Equal Substrings With Minimum Difference	Greedy,String	Medium	🔒
1795	Rearrange Products Table		Easy	🔒
1796	Second Largest Digit in a String	String	Easy
1797	Design Authentication Manager	Design,Hash Table	Medium
1798	Maximum Number of Consecutive Values You Can Make	Greedy	Medium
1799	Maximize Score After N Operations	Recursion,Dynamic Programming,Backtracking	Hard
1800	Maximum Ascending Subarray Sum	Two Pointers	Easy
1801	Number of Orders in the Backlog	Heap,Greedy	Medium
1802	Maximum Value at a Given Index in a Bounded Array	Greedy,Binary Search	Medium
1803	Count Pairs With XOR in a Range	Trie	Hard
1804	Implement Trie II (Prefix Tree)	Trie,String	Medium	🔒
1805	Number of Different Integers in a String	String	Easy
1806	Minimum Number of Operations to Reinitialize a Permutation	Greedy,Array	Medium
1807	Evaluate the Bracket Pairs of a String	Hash Table,String	Medium
1808	Maximize Number of Nice Divisors	Math	Hard
1809	Ad-Free Sessions		Easy	🔒
1810	Minimum Path Cost in a Hidden Grid	Heap,Depth-first Search,Graph	Medium	🔒
1811	Find Interview Candidates		Medium	🔒
1812	Determine Color of a Chessboard Square	String	Easy
1813	Sentence Similarity III	String	Medium
1814	Count Nice Pairs in an Array	Array,Hash Table	Medium
1815	Maximum Number of Groups Getting Fresh Donuts	Dynamic Programming	Hard
1816	Truncate Sentence	String	Easy
1817	Finding the Users Active Minutes	Hash Table	Medium
1818	Minimum Absolute Sum Difference	Greedy,Binary Search	Medium
1819	Number of Different Subsequences GCDs	Math	Hard
1820	Maximum Number of Accepted Invitations	Graph	Medium	🔒
1821	Find Customers With Positive Revenue this Year		Easy	🔒
1822	Sign of the Product of an Array	Math	Easy
1823	Find the Winner of the Circular Game	Array	Medium
1824	Minimum Sideway Jumps	Breadth-first Search,Dynamic Programming	Medium
1825	Finding MK Average	Heap,Design,Queue	Hard
1826	Faulty Sensor	Array	Easy	🔒
1827	Minimum Operations to Make the Array Increasing	Greedy,Array	Easy
1828	Queries on Number of Points Inside a Circle	Math	Medium
1829	Maximum XOR for Each Query	Bit Manipulation	Medium
1830	Minimum Number of Operations to Make String Sorted	Math,String	Hard
1831	Maximum Transaction Each Day		Medium	🔒
1832	Check if the Sentence Is Pangram	String	Easy
1833	Maximum Ice Cream Bars	Sort,Array	Medium
1834	Single-Threaded CPU	Heap	Medium
1835	Find XOR Sum of All Pairs Bitwise AND	Math	Hard
1836	Remove Duplicates From an Unsorted Linked List	Linked List	Medium	🔒
1837	Sum of Digits in Base K	Bit Manipulation,Math	Easy
1838	Frequency of the Most Frequent Element	Greedy	Medium
1839	Longest Substring Of All Vowels in Order	Two Pointers,String	Medium
1840	Maximum Building Height	Greedy,Binary Search	Hard
1841	League Statistics		Medium	🔒
1842	Next Palindrome Using Same Digits	Greedy	Hard	🔒
1843	Suspicious Bank Accounts		Medium	🔒
1844	Replace All Digits with Characters	String	Easy
1845	Seat Reservation Manager	Heap,Design	Medium
1846	Maximum Element After Decreasing and Rearranging	Greedy,Sort	Medium
1847	Closest Room	Sort,Binary Search	Hard
1848	Minimum Distance to the Target Element	Array	Easy
1849	Splitting a String Into Descending Consecutive Values	Recursion,String,Backtracking	Medium
1850	Minimum Adjacent Swaps to Reach the Kth Smallest Number	Greedy,String	Medium
1851	Minimum Interval to Include Each Query	Line Sweep	Hard
1852	Distinct Numbers in Each Subarray	Array,Hash Table,Line Sweep	Medium	🔒
1853	Convert Date Format		Easy	🔒
1854	Maximum Population Year	Array	Easy
1855	Maximum Distance Between a Pair of Values	Greedy,Two Pointers,Binary Search	Medium
1856	Maximum Subarray Min-Product	Sort,Union Find,Queue,Binary Search,Dynamic Programming	Medium
1857	Largest Color Value in a Directed Graph	Topological Sort,Dynamic Programming	Hard
1858	Longest Word With All Prefixes	Depth-first Search,Trie,Hash Table	Medium	🔒
1859	Sorting the Sentence	Sort,String	Easy
1860	Incremental Memory Leak	Math	Medium
1861	Rotating the Box	Array,Two Pointers	Medium
1862	Sum of Floored Pairs	Math	Hard
1863	Sum of All Subset XOR Totals	Recursion,Backtracking	Easy
1864	Minimum Number of Swaps to Make the Binary String Alternating	Greedy	Medium
1865	Finding Pairs With a Certain Sum	Design,Hash Table,Ordered Map	Medium
1866	Number of Ways to Rearrange Sticks With K Sticks Visible	Dynamic Programming	Hard
1867	Orders With Maximum Quantity Above Average		Medium	🔒
1868	Product of Two Run-Length Encoded Arrays	Two Pointers	Medium	🔒
1869	Longer Contiguous Segments of Ones than Zeros	Array,Two Pointers	Easy
1870	Minimum Speed to Arrive on Time	Math,Binary Search	Medium
1871	Jump Game VII	Greedy,Breadth-first Search,Line Sweep	Medium
1872	Stone Game VIII	Dynamic Programming	Hard
1873	Calculate Special Bonus		Easy	🔒
1874	Minimize Product Sum of Two Arrays	Greedy	Medium	🔒
1875	Group Employees of the Same Salary		Medium	🔒
1876	Substrings of Size Three with Distinct Characters	String	Easy
1877	Minimize Maximum Pair Sum in Array	Greedy,Sort	Medium
1878	Get Biggest Three Rhombus Sums in a Grid	Array,Math	Medium
1879	Minimum XOR Sum of Two Arrays	Bit Manipulation,Dynamic Programming	Hard
1880	Check if Word Equals Summation of Two Words	String	Easy
1881	Maximum Value after Insertion	Greedy	Medium
1882	Process Tasks Using Servers	Heap	Medium
1883	Minimum Skips to Arrive at Meeting On Time	Dynamic Programming	Hard

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