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 58 Generate All String Permutations Hard % 0 57 Sort an Array According to the Order Defined by Another Array Medium % 0 56 Sort an Array - odd numbers appear first in ascending order followed by the even numbers in descending order. Medium % 0 55 Print Nodes Between Two Levels in Binary Tree Medium % 0 54 Maximum Width of a Binary Tree Medium % 0 53 Count occurrences of a number in a sorted array Medium % 0 52 Find Common Numbers in Three Sorted Arrays Beginner % 0 51 Print Binary Tree Nodes in Zigzag Order: Spiral Traversal Pattern Hard % 0 50 Find the first repeated element in an array by its index Medium % 0 49 Find the Unreachable Minimum in Array Subsets Medium % 0 48 Determining Whether a Given Binary Tree is a Binary Search Tree (BST) Medium % 1 47 Find the Size of the Binary Tree Beginner % 0 46 Check if One Binary Tree is a Subtree of Another Medium % 0 45 Print a path from Root to Node in Binary Tree Medium % 0 44 Inorder Successor in Binary Tree Medium % 0 43 Inorder Successor in Binary Search Tree without Using Parent link Hard % 0 42 Inorder Successor in Binary Search Tree Using Parent link Hard % 0 41 Sorted Array to Binary Search Tree of Minimal Height Medium % 1 40 In a Binary Tree, Create Linked Lists of all the nodes at each depth Hard % 0 39 Level Order Traversal, Print each level in separate line Medium % 0 38 Determining Binary Tree Balance Medium % 0 37 Get the Height of a Node in a Binary Tree Medium % 0 36 Find the Maximum Depth OR Height of a Binary Tree Beginner % 1 35 Adding Two Numbers with Linked Lists Medium % 0 34 Add two numbers represented by a linked list, Numbers are Stored in REVERSE order Medium % 0 33 Reverse the binary representation of a number. Medium % 1 32 Binary Search Tree (BST) Complete Implementation. Beginner % 0 31 Reverse a Linked List Using Recursion Medium % 0 30 Swap Every Kth Node in a LinkedList Medium % 0 29 Delete a Node in the Middle of a Linked List Without Access to Head Node Beginner % 0 28 Determine the Nth Node from the Tail in a Linked List Beginner % 0 27 Remove Duplicates from an Unsorted Linked list Beginner % 0 26 Check if one string is Rotation of another string Beginner % 1 25 String Compression using count of repeated characters - Run Length Encoding Beginner % 0 24 Replace Spaces with '%20' Without Using Default Functions Medium % 0 Generate All String Permutations Sort an Array According to the Order Defined by Another Array Sort an Array - odd numbers appear first in ascending order followed by the even numbers in descending order. Print Nodes Between Two Levels in Binary Tree Maximum Width of a Binary Tree Count occurrences of a number in a sorted array Find Common Numbers in Three Sorted Arrays Print Binary Tree Nodes in Zigzag Order: Spiral Traversal Pattern Find the first repeated element in an array by its index Find the Unreachable Minimum in Array Subsets Determining Whether a Given Binary Tree is a Binary Search Tree (BST) Find the Size of the Binary Tree Check if One Binary Tree is a Subtree of Another Print a path from Root to Node in Binary Tree Inorder Successor in Binary Tree Inorder Successor in Binary Search Tree without Using Parent link Inorder Successor in Binary Search Tree Using Parent link Sorted Array to Binary Search Tree of Minimal Height In a Binary Tree, Create Linked Lists of all the nodes at each depth Level Order Traversal, Print each level in separate line Determining Binary Tree Balance Get the Height of a Node in a Binary Tree Find the Maximum Depth OR Height of a Binary Tree Adding Two Numbers with Linked Lists Add two numbers represented by a linked list, Numbers are Stored in REVERSE order Reverse the binary representation of a number. Binary Search Tree (BST) Complete Implementation. Reverse a Linked List Using Recursion Swap Every Kth Node in a LinkedList Delete a Node in the Middle of a Linked List Without Access to Head Node Determine the Nth Node from the Tail in a Linked List Remove Duplicates from an Unsorted Linked list Check if one string is Rotation of another string String Compression using count of repeated characters - Run Length Encoding Replace Spaces with '%20' Without Using Default Functions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16