💠 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.