💠 Find pair that sums upto K.
💠 First repeating character.
💠 Remove duplicates.
💠 Find Duplicate.
💠 Depth First Search(Preorder,Inorder,Postorder), Breadth First Search (Levelorder) in Binary Tree.
💠 Maximum Subarray.
💠 Invert Binary Tree.
💠 Longest substring without repeating character.
💠 Reverse linked list.
💠 Peak finding (peak index in an mountain array, peak element).
💠 Palindrome linked list.
💠 Longest Palindrome substring (or subsequence).
💠 Get substring index.
💠 Sort a linked list.
💠 Valid binary search tree.
💠 Minimum cost path in matrix.
💠 Balanced binary tree.
💠 Paths in matrix.
💠 Product of array except self.
💠 Jump to last index.
💠 Graph DFS, BFS.
💠 String Subsequences.
💠 Valid Brackets.
💠 Flatten a binary tree.
💠 Lowest common ancestor.
💠 Minimum in rotated sorted array.
💠 Add two linked list.
💠 Way to climb stairs.
💠 Subsets that sum upto k.
💠 Ways to decode.
💠 Remove node from BST.
💠 Array permutations.
💠 Longest Common Subsequence.
💠 Longest Consecutive sequence.
💠 Count sorted vowel strings.
💠 Smallest number after removing k digits.
💠 Merge Intervals.
💠 Insert intervals.
💠 Binary tree max sum.
💠 0-1 knapsack.
💠 Shortest palindrome.
💠 Coin change.
💠 Word search.
💠 N-queens.
💠 Word ladder.
💠 Longest increasing subsequence.