Heap Sort – Java Implementation
What is Heap Sort?? Heap sort is comparison based sorting algorithm. Heap sort is considered as improved selection sort, it divides the input into sorted and unsorted region. The improvement from selection sort is...
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Find no of reverse pairs in an array which is sorted in two parts in O(N)
Objective: Given an array of integers A[] which is sorted in two parts (both parts are individually sorted), find no of reverse pairs means no of (i, j) pairs where i belongs to the...
Get the Sum of Digits in a number till it become a single digit
Objective – Given a number, Write a program to get the sum of digits in a number till it become a single digit. Example: N = 999 -> 9+9+9 = 27-> 2+7 = 9...
Check if given number is Prime – O(√N) Solution – Java Program
Objective: Given a number, write a program to check if the number is prime or not. Prime Number: A number is called a prime number when number is not divisible by 1 or by...
Fizz Buzz Challenge – Java Implementation
Objective: Write a program that prints the numbers from 1 to 100. But for multiples of three print “Fizz” instead of the number and for the multiples of five print “Buzz”. For numbers which...
Graph – Detect Cycle in Undirected Graph using DFS
Objective: Given undirected graph write an algorithm to find out whether graph contains cycle or not. Example: Approach: Earlier we have seen how to find cycles in directed graphs. In this article we will...
Graph – Detect Cycle in a Directed Graph
Objective: Given a directed graph write an algorithm to find out whether graph contains cycle or not. Example: Approach: Graph contains cycle if there are any back edges. There are two types of back...
Graph – Software Installation Problem
Objective: Given a list of software’s which you need to install in a computer. Few software’s has dependency on other software’s in the list, means these software can be installed only when all of...
Topological Sort
Topological Sort: A topological sort or topological ordering of a directed graph is a linear ordering of its vertices such that for every directed edge uv from vertex u to vertex v, u comes before v in the ordering. A topological ordering is possible if and only if the graph has no directed...
Sliding Window Algorithm (Track the maximum of each subarray of size k)
Objective: Given an array and integer k, write an algorithm to find the maximum element in each subarray of size k. Example: int [] nums = { 1, 2, 3, 2, 4, 1, 5,...
Print all sub sequences of a given array
Objective: Given an array write an algorithm to print all the possible sub subsequences. Example: int [] a = {1, 2, 3}; Output: Possible sub sequences – {Empty}, {1}, {2}, {3}, {1, 2} ,{1,3}, {2,...
Remove Duplicates from a string
Objective: Given a string, write an algorithm to remove the duplicate characters in that string. Example: Input: tutorialhorizon Output: tuorialhzn Approaches: There are multiple approaches to solve this problem- Use Sorting – (Will change the...
Dynamic programming – Minimum Jumps to reach to end
Objective: Given an array of non negative integers, start from the first element and reach the last by jumping. The jump length can be at most the value at the current position in the array....
Find three elements in an array that sum to a given value
Objective: Given an array of integer write an algorithm to find 3 elements that sum to a given number k. In short a+b+c = k. Example: int a [] = { 3,1,7,4,5,9,10} , k =...
Majority Element- Boyer–Moore majority vote algorithm
Objective: Given an array of integer write an algorithm to find the majority element in it (if exist). Majority Element: If an element appears more than n/2 times in array where n is the size...