leetcode Algorithms Array 4. Median of Two Sorted Arrays 27. Remove Element 169. Majority Element 287. Find the Duplicate Number 896. Monotonic Array 905. Sort Array By Parity 1048. Longest String Chain TwoPointers 392. Is Subsequence HashTable 389. Find the Difference DynamicProgramming 799. Champagne Tower 1658. Minimum Operations to Reduce X to Zero Linked List 2. Add Two Numbers 21. Merge Two Sorted Lists 61. Rotate List 138. Copy List with Random Pointer 141. Linked List Cycle 146. LRU Cache