list-02

Question	Free?	Status	Difficulty	Topics	Similar Questions
101. Symmetric Tree  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗
102. Binary Tree Level Order Traversal  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Breadth-First Search  🔗 Binary Tree  🔗	103. Binary Tree Zigzag Level Order Traversal  🔗  📝 107. Binary Tree Level Order Traversal II  🔗  📝 111. Minimum Depth of Binary Tree  🔗  📝 314. Binary Tree Vertical Order Traversal  🔗  📝 429. N-ary Tree Level Order Traversal  🔗  📝 637. Average of Levels in Binary Tree  🔗  📝 993. Cousins in Binary Tree  🔗  📝
103. Binary Tree Zigzag Level Order Traversal  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Breadth-First Search  🔗 Binary Tree  🔗	102. Binary Tree Level Order Traversal  🔗  📝
104. Maximum Depth of Binary Tree  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗	110. Balanced Binary Tree  🔗  📝 111. Minimum Depth of Binary Tree  🔗  📝 559. Maximum Depth of N-ary Tree  🔗  📝 1376. Time Needed to Inform All Employees  🔗  📝
105. Construct Binary Tree from Preorder and Inorder Traversal  🔗  📝	🆓		⭐️⭐️	Array  🔗 Hash Table  🔗 Divide and Conquer  🔗 Tree  🔗 Binary Tree  🔗	106. Construct Binary Tree from Inorder and Postorder Traversal  🔗  📝
106. Construct Binary Tree from Inorder and Postorder Traversal  🔗  📝	🆓		⭐️⭐️	Array  🔗 Hash Table  🔗 Divide and Conquer  🔗 Tree  🔗 Binary Tree  🔗	105. Construct Binary Tree from Preorder and Inorder Traversal  🔗  📝
107. Binary Tree Level Order Traversal II  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Breadth-First Search  🔗 Binary Tree  🔗	102. Binary Tree Level Order Traversal  🔗  📝 637. Average of Levels in Binary Tree  🔗  📝
108. Convert Sorted Array to Binary Search Tree  🔗  📝	🆓		⭐️	Array  🔗 Divide and Conquer  🔗 Tree  🔗 Binary Search Tree  🔗 Binary Tree  🔗	109. Convert Sorted List to Binary Search Tree  🔗  📝
109. Convert Sorted List to Binary Search Tree  🔗  📝	🆓		⭐️⭐️	Linked List  🔗 Divide and Conquer  🔗 Tree  🔗 Binary Search Tree  🔗 Binary Tree  🔗	108. Convert Sorted Array to Binary Search Tree  🔗  📝 2196. Create Binary Tree From Descriptions  🔗  📝
110. Balanced Binary Tree  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	104. Maximum Depth of Binary Tree  🔗  📝
111. Minimum Depth of Binary Tree  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗	102. Binary Tree Level Order Traversal  🔗  📝 104. Maximum Depth of Binary Tree  🔗  📝
112. Path Sum  🔗  📝	🆓	✅	⭐️	Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗	113. Path Sum II  🔗  📝 124. Binary Tree Maximum Path Sum  🔗  📝 129. Sum Root to Leaf Numbers  🔗  📝 437. Path Sum III  🔗  📝 666. Path Sum IV  🔗  📝
113. Path Sum II  🔗  📝	🆓	✅	⭐️⭐️	Backtracking  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	112. Path Sum  🔗  📝 257. Binary Tree Paths  🔗  📝 437. Path Sum III  🔗  📝 666. Path Sum IV  🔗  📝 2096. Step-By-Step Directions From a Binary Tree Node to Another  🔗  📝
114. Flatten Binary Tree to Linked List  🔗  📝	🆓	✅	⭐️⭐️	Linked List  🔗 Stack  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	430. Flatten a Multilevel Doubly Linked List  🔗  📝 1660. Correct a Binary Tree  🔗  📝
115. Distinct Subsequences  🔗  📝	🆓		⭐️⭐️⭐️	String  🔗 Dynamic Programming  🔗	1987. Number of Unique Good Subsequences  🔗  📝
116. Populating Next Right Pointers in Each Node  🔗  📝	🆓	✅	⭐️⭐️	Linked List  🔗 Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗	117. Populating Next Right Pointers in Each Node II  🔗  📝 199. Binary Tree Right Side View  🔗  📝
117. Populating Next Right Pointers in Each Node II  🔗  📝	🆓	✅	⭐️⭐️	Linked List  🔗 Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗	116. Populating Next Right Pointers in Each Node  🔗  📝
118. Pascal's Triangle  🔗  📝	🆓	✅	⭐️	Array  🔗 Dynamic Programming  🔗	119. Pascal's Triangle II  🔗  📝
119. Pascal's Triangle II  🔗  📝	🆓	✅	⭐️	Array  🔗 Dynamic Programming  🔗	118. Pascal's Triangle  🔗  📝 2221. Find Triangular Sum of an Array  🔗  📝
120. Triangle  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Dynamic Programming  🔗
121. Best Time to Buy and Sell Stock  🔗  📝	🆓	✅	⭐️	Array  🔗 Dynamic Programming  🔗	53. Maximum Subarray  🔗  📝 122. Best Time to Buy and Sell Stock II  🔗  📝 123. Best Time to Buy and Sell Stock III  🔗  📝 188. Best Time to Buy and Sell Stock IV  🔗  📝 309. Best Time to Buy and Sell Stock with Cooldown  🔗  📝 2012. Sum of Beauty in the Array  🔗  📝 2016. Maximum Difference Between Increasing Elements  🔗  📝 2291. Maximum Profit From Trading Stocks  🔗  📝
122. Best Time to Buy and Sell Stock II  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Dynamic Programming  🔗 Greedy  🔗	121. Best Time to Buy and Sell Stock  🔗  📝 123. Best Time to Buy and Sell Stock III  🔗  📝 188. Best Time to Buy and Sell Stock IV  🔗  📝 309. Best Time to Buy and Sell Stock with Cooldown  🔗  📝 714. Best Time to Buy and Sell Stock with Transaction Fee  🔗  📝 2291. Maximum Profit From Trading Stocks  🔗  📝
123. Best Time to Buy and Sell Stock III  🔗  📝	🆓	👀	⭐️⭐️⭐️	Array  🔗 Dynamic Programming  🔗	121. Best Time to Buy and Sell Stock  🔗  📝 122. Best Time to Buy and Sell Stock II  🔗  📝 188. Best Time to Buy and Sell Stock IV  🔗  📝 689. Maximum Sum of 3 Non-Overlapping Subarrays  🔗  📝 2291. Maximum Profit From Trading Stocks  🔗  📝
124. Binary Tree Maximum Path Sum  🔗  📝	🆓		⭐️⭐️⭐️	Dynamic Programming  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	112. Path Sum  🔗  📝 129. Sum Root to Leaf Numbers  🔗  📝 666. Path Sum IV  🔗  📝 687. Longest Univalue Path  🔗  📝 1376. Time Needed to Inform All Employees  🔗  📝
125. Valid Palindrome  🔗  📝	🆓	✅	⭐️	Two Pointers  🔗 String  🔗	234. Palindrome Linked List  🔗  📝 680. Valid Palindrome II  🔗  📝 2002. Maximum Product of the Length of Two Palindromic Subsequences  🔗  📝 2108. Find First Palindromic String in the Array  🔗  📝 2330. Valid Palindrome IV  🔗  📝
126. Word Ladder II  🔗  📝	🆓	✅	⭐️⭐️⭐️	Hash Table  🔗 String  🔗 Backtracking  🔗 Breadth-First Search  🔗	127. Word Ladder  🔗  📝 2157. Groups of Strings  🔗  📝
127. Word Ladder  🔗  📝	🆓	✅	⭐️⭐️⭐️	Hash Table  🔗 String  🔗 Breadth-First Search  🔗	126. Word Ladder II  🔗  📝 433. Minimum Genetic Mutation  🔗  📝
128. Longest Consecutive Sequence  🔗  📝	🆓		⭐️⭐️	Array  🔗 Hash Table  🔗 Union Find  🔗	298. Binary Tree Longest Consecutive Sequence  🔗  📝 2177. Find Three Consecutive Integers That Sum to a Given Number  🔗  📝 2274. Maximum Consecutive Floors Without Special Floors  🔗  📝
129. Sum Root to Leaf Numbers  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	112. Path Sum  🔗  📝 124. Binary Tree Maximum Path Sum  🔗  📝 988. Smallest String Starting From Leaf  🔗  📝
130. Surrounded Regions  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Union Find  🔗 Matrix  🔗	200. Number of Islands  🔗  📝 286. Walls and Gates  🔗  📝
131. Palindrome Partitioning  🔗  📝	🆓		⭐️⭐️	String  🔗 Dynamic Programming  🔗 Backtracking  🔗	132. Palindrome Partitioning II  🔗  📝 1745. Palindrome Partitioning IV  🔗  📝
132. Palindrome Partitioning II  🔗  📝	🆓		⭐️⭐️⭐️	String  🔗 Dynamic Programming  🔗	131. Palindrome Partitioning  🔗  📝 1745. Palindrome Partitioning IV  🔗  📝
133. Clone Graph  🔗  📝	🆓	✅	⭐️⭐️	Hash Table  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Graph  🔗	138. Copy List with Random Pointer  🔗  📝 1485. Clone Binary Tree With Random Pointer  🔗  📝 1490. Clone N-ary Tree  🔗  📝
134. Gas Station  🔗  📝	🆓		⭐️⭐️	Array  🔗 Greedy  🔗	2202. Maximize the Topmost Element After K Moves  🔗  📝
135. Candy  🔗  📝	🆓		⭐️⭐️⭐️	Array  🔗 Greedy  🔗	2371. Minimize Maximum Value in a Grid  🔗  📝
136. Single Number  🔗  📝	🆓	✅	⭐️	Array  🔗 Bit Manipulation  🔗	137. Single Number II  🔗  📝 260. Single Number III  🔗  📝 268. Missing Number  🔗  📝 287. Find the Duplicate Number  🔗  📝 389. Find the Difference  🔗  📝
137. Single Number II  🔗  📝	🆓		⭐️⭐️	Array  🔗 Bit Manipulation  🔗	136. Single Number  🔗  📝 260. Single Number III  🔗  📝
138. Copy List with Random Pointer  🔗  📝	🆓	✅	⭐️⭐️	Hash Table  🔗 Linked List  🔗	133. Clone Graph  🔗  📝 1485. Clone Binary Tree With Random Pointer  🔗  📝 1490. Clone N-ary Tree  🔗  📝
139. Word Break  🔗  📝	🆓		⭐️⭐️	Hash Table  🔗 String  🔗 Dynamic Programming  🔗 Trie  🔗 Memoization  🔗	140. Word Break II  🔗  📝
140. Word Break II  🔗  📝	🆓		⭐️⭐️⭐️	Hash Table  🔗 String  🔗 Dynamic Programming  🔗 Backtracking  🔗 Trie  🔗 Memoization  🔗	139. Word Break  🔗  📝 472. Concatenated Words  🔗  📝
141. Linked List Cycle  🔗  📝	🆓	✅	⭐️	Hash Table  🔗 Linked List  🔗 Two Pointers  🔗	142. Linked List Cycle II  🔗  📝 202. Happy Number  🔗  📝
142. Linked List Cycle II  🔗  📝	🆓	✅	⭐️⭐️	Hash Table  🔗 Linked List  🔗 Two Pointers  🔗	141. Linked List Cycle  🔗  📝 287. Find the Duplicate Number  🔗  📝
143. Reorder List  🔗  📝	🆓	✅	⭐️⭐️	Linked List  🔗 Two Pointers  🔗 Stack  🔗 Recursion  🔗	2095. Delete the Middle Node of a Linked List  🔗  📝
144. Binary Tree Preorder Traversal  🔗  📝	🆓	✅	⭐️	Stack  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	94. Binary Tree Inorder Traversal  🔗  📝 255. Verify Preorder Sequence in Binary Search Tree  🔗  📝 589. N-ary Tree Preorder Traversal  🔗  📝
145. Binary Tree Postorder Traversal  🔗  📝	🆓	✅	⭐️	Stack  🔗 Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	94. Binary Tree Inorder Traversal  🔗  📝 590. N-ary Tree Postorder Traversal  🔗  📝
146. LRU Cache  🔗  📝	🆓		⭐️⭐️	Hash Table  🔗 Linked List  🔗 Design  🔗 Doubly-Linked List  🔗	460. LFU Cache  🔗  📝 588. Design In-Memory File System  🔗  📝 604. Design Compressed String Iterator  🔗  📝 1756. Design Most Recently Used Queue  🔗  📝
147. Insertion Sort List  🔗  📝	🆓	✅	⭐️⭐️	Linked List  🔗 Sorting  🔗	148. Sort List  🔗  📝 708. Insert into a Sorted Circular Linked List  🔗  📝
148. Sort List  🔗  📝	🆓	✅	⭐️⭐️	Linked List  🔗 Two Pointers  🔗 Divide and Conquer  🔗 Sorting  🔗 Merge Sort  🔗	21. Merge Two Sorted Lists  🔗  📝 75. Sort Colors  🔗  📝 147. Insertion Sort List  🔗  📝 2046. Sort Linked List Already Sorted Using Absolute Values  🔗  📝
149. Max Points on a Line  🔗  📝	🆓	✅	⭐️⭐️⭐️	Array  🔗 Hash Table  🔗 Math  🔗 Geometry  🔗	356. Line Reflection  🔗  📝 2152. Minimum Number of Lines to Cover Points  🔗  📝 2280. Minimum Lines to Represent a Line Chart  🔗  📝
150. Evaluate Reverse Polish Notation  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Math  🔗 Stack  🔗	224. Basic Calculator  🔗  📝 282. Expression Add Operators  🔗  📝
151. Reverse Words in a String  🔗  📝	🆓	✅	⭐️⭐️	Two Pointers  🔗 String  🔗	186. Reverse Words in a String II  🔗  📝
152. Maximum Product Subarray  🔗  📝	🆓	👀	⭐️⭐️	Array  🔗 Dynamic Programming  🔗	53. Maximum Subarray  🔗  📝 198. House Robber  🔗  📝 238. Product of Array Except Self  🔗  📝 628. Maximum Product of Three Numbers  🔗  📝 713. Subarray Product Less Than K  🔗  📝
153. Find Minimum in Rotated Sorted Array  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Binary Search  🔗	33. Search in Rotated Sorted Array  🔗  📝 154. Find Minimum in Rotated Sorted Array II  🔗  📝
154. Find Minimum in Rotated Sorted Array II  🔗  📝	🆓		⭐️⭐️⭐️	Array  🔗 Binary Search  🔗	153. Find Minimum in Rotated Sorted Array  🔗  📝
155. Min Stack  🔗  📝	🆓		⭐️⭐️	Stack  🔗 Design  🔗	239. Sliding Window Maximum  🔗  📝 716. Max Stack  🔗  📝
156. Binary Tree Upside Down  🔗  📝	💰		⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Binary Tree  🔗	206. Reverse Linked List  🔗  📝
157. Read N Characters Given Read4  🔗  📝	💰		⭐️	String  🔗 Simulation  🔗 Interactive  🔗	158. Read N Characters Given read4 II - Call Multiple Times  🔗  📝
158. Read N Characters Given read4 II - Call Multiple Times  🔗  📝	💰		⭐️⭐️⭐️	String  🔗 Simulation  🔗 Interactive  🔗	157. Read N Characters Given Read4  🔗  📝
159. Longest Substring with At Most Two Distinct Characters  🔗  📝	💰		⭐️⭐️	Hash Table  🔗 String  🔗 Sliding Window  🔗	3. Longest Substring Without Repeating Characters  🔗  📝 239. Sliding Window Maximum  🔗  📝 340. Longest Substring with At Most K Distinct Characters  🔗  📝 992. Subarrays with K Different Integers  🔗  📝
160. Intersection of Two Linked Lists  🔗  📝	🆓	✅	⭐️	Hash Table  🔗 Linked List  🔗 Two Pointers  🔗	599. Minimum Index Sum of Two Lists  🔗  📝
161. One Edit Distance  🔗  📝	💰		⭐️⭐️	Two Pointers  🔗 String  🔗	72. Edit Distance  🔗  📝
162. Find Peak Element  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Binary Search  🔗	852. Peak Index in a Mountain Array  🔗  📝 1901. Find a Peak Element II  🔗  📝 2137. Pour Water Between Buckets to Make Water Levels Equal  🔗  📝 2210. Count Hills and Valleys in an Array  🔗  📝
163. Missing Ranges  🔗  📝	💰		⭐️	Array  🔗	228. Summary Ranges  🔗  📝
164. Maximum Gap  🔗  📝	🆓	👀	⭐️⭐️⭐️	Array  🔗 Sorting  🔗 Bucket Sort  🔗 Radix Sort  🔗	2274. Maximum Consecutive Floors Without Special Floors  🔗  📝
165. Compare Version Numbers  🔗  📝	🆓		⭐️⭐️	Two Pointers  🔗 String  🔗
166. Fraction to Recurring Decimal  🔗  📝	🆓		⭐️⭐️	Hash Table  🔗 Math  🔗 String  🔗
167. Two Sum II - Input Array Is Sorted  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Two Pointers  🔗 Binary Search  🔗	1. Two Sum  🔗  📝 653. Two Sum IV - Input is a BST  🔗  📝 1099. Two Sum Less Than K  🔗  📝
168. Excel Sheet Column Title  🔗  📝	🆓	👀	⭐️	Math  🔗 String  🔗	171. Excel Sheet Column Number  🔗  📝 2194. Cells in a Range on an Excel Sheet  🔗  📝
169. Majority Element  🔗  📝	🆓	✅	⭐️	Array  🔗 Hash Table  🔗 Divide and Conquer  🔗 Sorting  🔗 Counting  🔗	229. Majority Element II  🔗  📝 1150. Check If a Number Is Majority Element in a Sorted Array  🔗  📝
170. Two Sum III - Data structure design  🔗  📝	💰		⭐️	Array  🔗 Hash Table  🔗 Two Pointers  🔗 Design  🔗 Data Stream  🔗	1. Two Sum  🔗  📝 288. Unique Word Abbreviation  🔗  📝 653. Two Sum IV - Input is a BST  🔗  📝
171. Excel Sheet Column Number  🔗  📝	🆓	✅	⭐️	Math  🔗 String  🔗	168. Excel Sheet Column Title  🔗  📝 2194. Cells in a Range on an Excel Sheet  🔗  📝
172. Factorial Trailing Zeroes  🔗  📝	🆓	✅	⭐️⭐️	Math  🔗	233. Number of Digit One  🔗  📝 793. Preimage Size of Factorial Zeroes Function  🔗  📝 2117. Abbreviating the Product of a Range  🔗  📝 2245. Maximum Trailing Zeros in a Cornered Path  🔗  📝
173. Binary Search Tree Iterator  🔗  📝	🆓	✅	⭐️⭐️	Stack  🔗 Tree  🔗 Design  🔗 Binary Search Tree  🔗 Binary Tree  🔗 Iterator  🔗	94. Binary Tree Inorder Traversal  🔗  📝 251. Flatten 2D Vector  🔗  📝 281. Zigzag Iterator  🔗  📝 284. Peeking Iterator  🔗  📝 285. Inorder Successor in BST  🔗  📝 1586. Binary Search Tree Iterator II  🔗  📝
174. Dungeon Game  🔗  📝	🆓		⭐️⭐️⭐️	Array  🔗 Dynamic Programming  🔗 Matrix  🔗	62. Unique Paths  🔗  📝 64. Minimum Path Sum  🔗  📝 741. Cherry Pickup  🔗  📝 2214. Minimum Health to Beat Game  🔗  📝 2304. Minimum Path Cost in a Grid  🔗  📝
175. Combine Two Tables  🔗  📝	🆓	✅	⭐️	Database  🔗	577. Employee Bonus  🔗  📝
176. Second Highest Salary  🔗  📝	🆓		⭐️⭐️	Database  🔗
177. Nth Highest Salary  🔗  📝	🆓		⭐️⭐️	Database  🔗	2205. The Number of Users That Are Eligible for Discount  🔗  📝
178. Rank Scores  🔗  📝	🆓		⭐️⭐️	Database  🔗
179. Largest Number  🔗  📝	🆓		⭐️⭐️	String  🔗 Greedy  🔗 Sorting  🔗	2165. Smallest Value of the Rearranged Number  🔗  📝
180. Consecutive Numbers  🔗  📝	🆓		⭐️⭐️	Database  🔗
181. Employees Earning More Than Their Managers  🔗  📝	🆓		⭐️	Database  🔗
182. Duplicate Emails  🔗  📝	🆓		⭐️	Database  🔗
183. Customers Who Never Order  🔗  📝	🆓		⭐️	Database  🔗
184. Department Highest Salary  🔗  📝	🆓		⭐️⭐️	Database  🔗	1112. Highest Grade For Each Student  🔗  📝
185. Department Top Three Salaries  🔗  📝	🆓		⭐️⭐️⭐️	Database  🔗
186. Reverse Words in a String II  🔗  📝	💰		⭐️⭐️	Two Pointers  🔗 String  🔗	151. Reverse Words in a String  🔗  📝 189. Rotate Array  🔗  📝
187. Repeated DNA Sequences  🔗  📝	🆓		⭐️⭐️	Hash Table  🔗 String  🔗 Bit Manipulation  🔗 Sliding Window  🔗 Rolling Hash  🔗 Hash Function  🔗
188. Best Time to Buy and Sell Stock IV  🔗  📝	🆓		⭐️⭐️⭐️	Array  🔗 Dynamic Programming  🔗	121. Best Time to Buy and Sell Stock  🔗  📝 122. Best Time to Buy and Sell Stock II  🔗  📝 123. Best Time to Buy and Sell Stock III  🔗  📝 2291. Maximum Profit From Trading Stocks  🔗  📝
189. Rotate Array  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Math  🔗 Two Pointers  🔗	61. Rotate List  🔗  📝 186. Reverse Words in a String II  🔗  📝
190. Reverse Bits  🔗  📝	🆓	✅	⭐️	Divide and Conquer  🔗 Bit Manipulation  🔗	7. Reverse Integer  🔗  📝 191. Number of 1 Bits  🔗  📝 2119. A Number After a Double Reversal  🔗  📝
191. Number of 1 Bits  🔗  📝	🆓	✅	⭐️	Divide and Conquer  🔗 Bit Manipulation  🔗	190. Reverse Bits  🔗  📝 231. Power of Two  🔗  📝 338. Counting Bits  🔗  📝 401. Binary Watch  🔗  📝 461. Hamming Distance  🔗  📝 693. Binary Number with Alternating Bits  🔗  📝 762. Prime Number of Set Bits in Binary Representation  🔗  📝
192. Word Frequency  🔗  📝	🆓		⭐️⭐️	Shell  🔗	347. Top K Frequent Elements  🔗  📝
193. Valid Phone Numbers  🔗  📝	🆓		⭐️	Shell  🔗
194. Transpose File  🔗  📝	🆓		⭐️⭐️	Shell  🔗
195. Tenth Line  🔗  📝	🆓		⭐️	Shell  🔗
196. Delete Duplicate Emails  🔗  📝	🆓		⭐️	Database  🔗
197. Rising Temperature  🔗  📝	🆓		⭐️	Database  🔗
198. House Robber  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Dynamic Programming  🔗	152. Maximum Product Subarray  🔗  📝 213. House Robber II  🔗  📝 256. Paint House  🔗  📝 276. Paint Fence  🔗  📝 337. House Robber III  🔗  📝 600. Non-negative Integers without Consecutive Ones  🔗  📝 656. Coin Path  🔗  📝 740. Delete and Earn  🔗  📝 2140. Solving Questions With Brainpower  🔗  📝 2320. Count Number of Ways to Place Houses  🔗  📝
199. Binary Tree Right Side View  🔗  📝	🆓	✅	⭐️⭐️	Tree  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Binary Tree  🔗	116. Populating Next Right Pointers in Each Node  🔗  📝 545. Boundary of Binary Tree  🔗  📝
200. Number of Islands  🔗  📝	🆓	✅	⭐️⭐️	Array  🔗 Depth-First Search  🔗 Breadth-First Search  🔗 Union Find  🔗 Matrix  🔗	130. Surrounded Regions  🔗  📝 286. Walls and Gates  🔗  📝 305. Number of Islands II  🔗  📝 323. Number of Connected Components in an Undirected Graph  🔗  📝 694. Number of Distinct Islands  🔗  📝 695. Max Area of Island  🔗  📝 1905. Count Sub Islands  🔗  📝 1992. Find All Groups of Farmland  🔗  📝 2316. Count Unreachable Pairs of Nodes in an Undirected Graph  🔗  📝