# Category Archives: Data Structures

Given a string, print all permutations of it in sorted order. For example, if the input string is “ABC”, then output should be “ABC, ACB,â€¦ Read More
Given a string str, find its rank among all its permutations when sorted lexicographically. Note: The characters a string are all unique. Examples: Input: strâ€¦ Read More
Given two arrays that represent preorder and postorder traversals of a full binary tree, construct the binary tree. Full Binary Tree is a binary treeâ€¦ Read More
Given an array where every element occurs three times, except one element which occurs only once. Find the element that occurs once. The expectedâ€¦ Read More
Given an array of non-negative integers. Find the largest multiple of 3 that can be formed from array elements. For example, if the input array isâ€¦ Read More
Given a linked list where every node represents a linked list and contains two pointers of its type:  Pointer to next node in the mainâ€¦ Read More
Given a binary matrix, print all unique rows of the given matrix.  Example:  Input: {0, 1, 0, 0, 1} {1, 0, 1, 1, 0} {0,â€¦ Read More
Given N machines. Each machine contains some numbers in sorted form. But the amount of numbers, each machine has is not fixed. Output the numbersâ€¦ Read More
Given a boolean 2D array, where each row is sorted. Find the row with the maximum number of 1s.  Example:   Input matrix : 0 1â€¦ Read More
Given a circular array of size n, find the maximum subarray sum of the non-empty subarray. Examples:  Input: arr[] = {8, -8, 9, -9, 10,â€¦ Read More
Two of the nodes of a Binary Search Tree (BST) are swapped. Fix (or correct) the BST.  Input: x = 20, y = 8    â€¦ Read More
Given a binary tree, print boundary nodes of the binary tree Anti-Clockwise starting from the root.  The boundary includes  left boundary (nodes on left excludingâ€¦ Read More
Given a number, find the next smallest palindrome larger than this number. For example, if the input number is “2 3 5 4 5”, theâ€¦ Read More
Given an array of N elements, where each element is at most K away from its target position, devise an algorithm that sorts in O(Nâ€¦ Read More