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 153 Find the Second Largest Element in an Array Beginner % 1 148 Backtracking - SUDOKU Solver Hard % 0 147 Introduction To Backtracking Programming Beginner % 0 143 Merge K Sorted Arrays Hard % 0 141 Find a Number occurring odd number of times in a Given array Beginner % 1 139 Find a Missing Number From a Sequence of Consecutive Numbers | XOR Method Beginner % 1 137 Populate Next Siblings Pointers in a Given Binary Tree OR Populate Next Right Pointers in Each Node Hard % 0 136 Check If One Binary is Mirror Tree of another Binary Tree. Beginner % 1 135 Print All Paths From Root In a Binary Tree Whose Sum is Equal to a Given Number Medium % 0 130 Print All The Full Nodes in a Binary Tree Beginner % 0 119 Clock Angle Problem Beginner % 1 118 Print All Combinations of subset of size K from Given Array Hard % 0 106 Reverse The Doubly Linked List Medium % 0 105 Swap Kth Node from the front with the Kth Node from the End Medium % 0 104 Print the Bottom View of the Binary Tree. Medium % 0 103 Delete X Nodes After Y Nodes In a Linked List Beginner % 0 101 Merge a Linked list into another Linked List at Alternate Positions. Medium % 0 99 Construct a binary tree from given Inorder and Level Order Traversal Hard % 0 98 Construct Binary Search Tree from a given Preorder Traversal Using Stack (Without Recursion) Hard % 0 96 Print The Top View of a Binary Tree Medium % 0 95 Construct a Binary Tree from Given Inorder and Depth-First-Search. Hard % 0 93 Inorder Predecessor and Successor in Binary Search Tree Hard % 0 88 Rearrange Positive and Negative Elements at Alternate Positions in an Array In O(1) Extra Space Hard % 0 84 Find All Elements in an Array which appears more than N/K times, N is Array Size and k is a Number. Hard % 0 80 Print All The Nodes Which are X distance from the Root Medium % 0 79 Find the Distance between Two Nodes of a Binary Tree. Hard % 0 78 Find The Distance From Root To Given Node of a Binary Tree. Medium % 0 77 Construct a binary tree from given Inorder and Postorder Traversal Hard % 0 76 Print the Vertical Sum in binary Tree Medium % 0 75 Print the Binary Tree in Vertical Order Path. Medium % 0 72 Make a Binary Tree from Given Inorder and Preorder Traversal Hard % 0 71 Given a binary tree, find out the maximum sum of value from root to each leaf. Medium % 0 70 Reverse Alternate levels of a given Binary 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 Find the Second Largest Element in an Array Backtracking - SUDOKU Solver Introduction To Backtracking Programming Merge K Sorted Arrays Find a Number occurring odd number of times in a Given array Find a Missing Number From a Sequence of Consecutive Numbers | XOR Method Populate Next Siblings Pointers in a Given Binary Tree OR Populate Next Right Pointers in Each Node Check If One Binary is Mirror Tree of another Binary Tree. Print All Paths From Root In a Binary Tree Whose Sum is Equal to a Given Number Print All The Full Nodes in a Binary Tree Clock Angle Problem Print All Combinations of subset of size K from Given Array Reverse The Doubly Linked List Swap Kth Node from the front with the Kth Node from the End Print the Bottom View of the Binary Tree. Delete X Nodes After Y Nodes In a Linked List Merge a Linked list into another Linked List at Alternate Positions. Construct a binary tree from given Inorder and Level Order Traversal Construct Binary Search Tree from a given Preorder Traversal Using Stack (Without Recursion) Print The Top View of a Binary Tree Construct a Binary Tree from Given Inorder and Depth-First-Search. Inorder Predecessor and Successor in Binary Search Tree Rearrange Positive and Negative Elements at Alternate Positions in an Array In O(1) Extra Space Find All Elements in an Array which appears more than N/K times, N is Array Size and k is a Number. Print All The Nodes Which are X distance from the Root Find the Distance between Two Nodes of a Binary Tree. Find The Distance From Root To Given Node of a Binary Tree. Construct a binary tree from given Inorder and Postorder Traversal Print the Vertical Sum in binary Tree Print the Binary Tree in Vertical Order Path. Make a Binary Tree from Given Inorder and Preorder Traversal Given a binary tree, find out the maximum sum of value from root to each leaf. Reverse Alternate levels of a given Binary Tree. Given a binary tree, Convert it into its Mirror Tree Given a binary tree, Print All the Nodes that don't have Siblings. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16