Detect a cycle in a undirected graph
Problem Statement: You are given a undirected graph. You need to find out if the graph contains cycle or not. Example Solution We can use DFS…
Detect a cycle in a directed graph
Problem Statement: You are given a directed graph. You need to find out if the graph contains cycle or not. Example Solution We shall use DFS…
Heaps: Merge “K” sorted arrays
Problem Statement: You are given k sorted arrays of size n each. You need to merge them and print the sorted output. Example k = 3, n = 4…
Heaps: Find kth smallest in an unsorted array
Problem Statement: You are given an array and a number K, you need to find the kth smallest element. Example Input: arr[] = {5, 20, 10, 7, 1},…
Heaps: Sort an Array using heap
Problem Statement: Given an array, sort it by using heap sort. Solution Relationship between array and heap elements. As we know that heaps…
Heaps: Build Min Heap from an Array
Problem Statement: You are given N array elements. You need to build a Min Heap. Solution Min Heap: The root element is greater than its…
Next Smaller Element
Problem Statement: YOu are given an unsorted array, you need to find the next smaller element for all the elements. Next smaller element for…
Reverse the first “K” elements of a queue
Problem Statement: You are given a queue and an element k, you need to reverse the first ‘k’ elements in the queue. Example Input:…
Queue Reversal
Problem Statement: Given a queue, you need to reverse it. Solution This problem can be solved in 2 different methods. Method 1: Using stack.…
Stack: Check if a stack is a permutation of another stack
Problem Statement: You are given 2 array, check one array is permutation of another array. Example Input : First array: 1, 2, 3 Second array:…