# Category: Software Development Engineer (SDE)

## Multiply with power of 2 without using pow() or * operator

Objective: Given a number n and k, Calculate n * k2 without using pow() or *operator. Example: N = 3, k = 4 N*k2 = 48 Approach: Bit Manipulation Left shift the number N...

## Find Number of reverse pairs in an array

Objective: Given an array of integers A[],find no of reverse pairs means no of (i, j) pairs where i < j and A[i]>A[j]. This problem is also asked as Count Inversions in an array....

## Calculate Logn base r – Java Implementation

Objective: Given a number n and r, write a program to calculate Logrn Example: N = 32, r =2 Log232= 5 N = 64, r = 4 Log464= 3 Approach: Without using built-In function-...

## Max Flow Problem – Introduction

Max Flow Problem- Maximum flow problems find a feasible flow through a single-source, single-sink flow network that is maximum. This problem is useful for solving complex network flow problems such as the circulation problem. The maximum value...

## Dijkstra Algorithm Implementation – TreeSet and Pair Class

Earlier we have seen what Dijkstra algorithm is is and how it works. In this article we will see its implementation using adjacency list and TreeSet. Example: Implementation – Adjacency List and Priority Queue...

## Check if Given Number is power of 2.

Objective: Given a number, write a program to find if number is power of two. Example: N = 5 Output: false. N = 8 Output: true (23) N = 512 Output: true (29) Approach:...

## 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...

## 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...

## Dijkstra’s – Shortest Path Algorithm (SPT) – Adjacency List and Priority Queue – Java Implementation

Earlier we have seen what Dijkstra’s algorithm is and how it works. In this article we will see its implementation using adjacency list and Priority Queue. Prerequisites: Adjacency List Priority Queue Dijkstra’s Algorithm basics...

## 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...

## Print First N Prime Numbers – Java Code

Objective: Given a number N, write a program to print first N prime numbers. What is Prime number:?? A prime number (or a prime) is a natural number greater than 1 that cannot be...

## Dijkstra’s – Shortest Path Algorithm (SPT) – Adjacency List and Min Heap – Java Implementation

Earlier we have seen the basics of Dijkstra algorithm. In this article we will see its implementation using adjacency list and Min Heap. We strongly recommend reading the following articles Dijkstra algorithm and how...

## Swap two numbers using Bitwise XOR Operator

Objective– Given two numbers, swap both the numbers using XOR operators. Example: X = 4, Y = 8 Output: X = 8, Y= 4 Approach: XOR operator There are many ways to swap two...

## Dijkstra’s – Shortest Path Algorithm (SPT) – Adjacency Matrix – Java Implementation

Earlier we have seen what Dijkstra’s algorithm is and how it works. In this article we will see its implementation using adjacency matrix. We strongly recommend reading – Dijkstra algorithm and how it works....

## 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...