Featured Lists Top 20 Problems on Dynamic programming Top 10 Problems on Backtracking Top 20 Problems on Graph Top 25 Problems on Trees Top 10 Problems on Bits Manipulation Top 15 Problems in LinkedList All Problems # Status Problem video Level Completes Likes 73 Lowest Common Ancestor in a Binary Search Tree. Medium % 0 68 Given a binary tree, Convert it into its Mirror Tree Beginner % 0 67 Given a binary tree, Print All the Nodes that don't have Siblings. Beginner % 0 66 Convert a Sorted Doubly Linked List to Balanced BST. Medium % 1 62 In a Binary Tree, Check if Two nodes has the same parent or are siblings Medium % 0 61 In a Binary Tree, Check if two nodes are Cousins Medium % 0 41 Sorted Array to Binary Search Tree of Minimal Height Medium % 1 37 Get the Height of a Node in a Binary Tree Medium % 0 23 Find Whether Two Strings are Permutation of each other Beginner % 1 20 Reverse a Linked List Beginner % 0 19 Exploring All Paths, Including Diagonal, from Top Left to Bottom Right in 2D Array Medium % 1 9 Valid or Well Formed Parentheses | Part - 1 Medium % 0 1 Binary Search Beginner % 0 550 Debugging Techniques- How to Efficiently Find and Fix Software Bugs Medium % 1 532 Maximum Depth of Valid Nested Parentheses in an arithmetic expression Medium % 0 526 Maximum Surpasser in the given array Hard % 0 524 Maximum CPU Load Problem in a jobs list Medium % 1 521 Maximum overlaps in a given list of time intervals Medium % 0 512 Override the compare function for Collections.sort method Beginner % 0 510 Design a data structure for Candidate Voting Problem Medium % 0 507 Design data structure for players and ranks Medium % 0 505 Override the compare function for Arrays.sort method - Java Beginner % 0 502 Calculate tax on income as per given tax brackets. Beginner % 0 498 The largest number can be formed from the given number Beginner % 0 497 Minimum number of adjacent swaps to sort the given array Hard % 1 492 Find the number of pairs with even XOR Beginner % 0 489 The number of cycles in a given array of integers. Hard % 0 488 Check if given sudoku is valid or not Medium % 0 487 Find Election Winner Beginner % 0 486 Sort the indexes of the array as per the elements of the array Medium % 0 485 Construct the Largest number from the given digits Beginner % 1 483 Find Lexicographically smallest or largest substring of size k Beginner % 0 482 Largest word in dictionary by removing a few characters from the given string Beginner % 0 480 Check if one string is a subsequence of another string. Beginner % 0 479 Most frequent word Beginner % 0 Lowest Common Ancestor in a Binary Search Tree. Given a binary tree, Convert it into its Mirror Tree Given a binary tree, Print All the Nodes that don't have Siblings. Convert a Sorted Doubly Linked List to Balanced BST. In a Binary Tree, Check if Two nodes has the same parent or are siblings In a Binary Tree, Check if two nodes are Cousins Sorted Array to Binary Search Tree of Minimal Height Get the Height of a Node in a Binary Tree Find Whether Two Strings are Permutation of each other Reverse a Linked List Exploring All Paths, Including Diagonal, from Top Left to Bottom Right in 2D Array Valid or Well Formed Parentheses | Part - 1 Binary Search Debugging Techniques- How to Efficiently Find and Fix Software Bugs Maximum Depth of Valid Nested Parentheses in an arithmetic expression Maximum Surpasser in the given array Maximum CPU Load Problem in a jobs list Maximum overlaps in a given list of time intervals Override the compare function for Collections.sort method Design a data structure for Candidate Voting Problem Design data structure for players and ranks Override the compare function for Arrays.sort method - Java Calculate tax on income as per given tax brackets. The largest number can be formed from the given number Minimum number of adjacent swaps to sort the given array Find the number of pairs with even XOR The number of cycles in a given array of integers. Check if given sudoku is valid or not Find Election Winner Sort the indexes of the array as per the elements of the array Construct the Largest number from the given digits Find Lexicographically smallest or largest substring of size k Largest word in dictionary by removing a few characters from the given string Check if one string is a subsequence of another string. Most frequent word 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16