Queue using Stacks

In queue using a stack problem, we have to implement the following functions of a queue using the standard functions of stack data structure, Enqueue: Add an element to the end of the queue Dequeue: Remove an element from the start of the queue Example Input: Enqueue(5) Enqueue(11) Enqueue(39) Dequeue()  …

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Trapping Rain Water LeetCode Solution

In the Trapping Rain Water LeetCode problem, we have given N non-negative integers representing an elevation map and the width of each bar is 1. We have to find the amount of water that can be trapped in the above structure. Example Let’s understand that by an example For the …

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Next Permutation

In the next permutation problem we have given a word, find the lexicographically greater_permutation of it. Example input : str = “tutorialcup” output : tutorialpcu input : str = “nmhdgfecba” output : nmheabcdfg input : str = “algorithms” output : algorithsm input : str = “spoonfeed” output : Next Permutation …

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Binary Tree zigzag level order Traversal

Given a binary tree, print the zigzag level order traversal of its node values. (ie, from left to right, then right to left for the next level and alternate between). Example consider the binary tree given below Below is the zigzag level order traversal of the above binary tree Types …

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Topological Sorting

Given a directed acyclic graph, topologically sort the graph nodes. Topological Sorting Example Topological sorting of above graph is -> {1,2,3,0,5,4} Theory Topological Sorting is done for a Directed Acyclic Graph (DAG). A DAG has no cycles in it. ie, there is no such path starting from any node of …

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Smallest Palindrome after Replacement

Problem Statement In the “Smallest Palindrome after Replacement” problem we have given the input string contains lower case alphabets characters and dots(.). We need to replace all dots with some alphabet character in such a way that the resultant string becomes a palindrome. The palindrome should be lexicographically smallest. Input …

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