# Category: Position

## Find the nearest building which has bike | Find nearest specific vertex from source in a graph.

Objective: Given a matrix (NxN) which represents the buildings in community. You are in a building and you need a bike to travel.  There are few buildings in community which has bikes which you...

## Valid Brackets – Part 2 | Stack Method

Objective: Given a string containing just the characters ( , ) determine if the input string is valid. Example: ()()(()(()))() valid: true )()()( valid: false ()()) valid: false Approach: Earlier we discussed the solution which keeps...

## Given two strings validate the output string

Objective: Given two input strings and one output strings, validate if output string contains all the characters from both the input strings. Example: Input1 = “boy”, Input2 = “girl”, output = “gboilry” Result =...

## Generate all the strings of length n from 0 to k-1.

Objective: Given two numbers, n and k (k>=n), write an algorithm to generate all the strings of length n drawn from 0 – k-1. Example: k = 2, n = 2Output:  0 0      0...

## Find two smallest elements in a given array

Objective: Given an array of integers, write an algorithm to find the two smallest elements in the array. Example: Int [] a = { 6, 8, 1, 9, 2, 10}; Output: 1, 2 Int...

## Print all Unique elements in a given array

Objective: Given an array of integers which contains duplicates as well. Write a program to print all unique elements in the array. This problem is also referred as print all distinct elements in the...

## 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]. Example: A[] = {10, 3, 4, 2, 5, 7, 9, 11}...

## Find first two largest elements in a given array

Objective: Given an array of integers, write an algorithm to find the first two largest elements in the array. Example: Int [] a = { 6, 8, 1, 9, 2, 1, 10}; Output: 10,...

## 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 solving complex network flow problems such as circulation problem. The maximum value of the...

## 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:...

## Rotate the given array in cycles

Objective: Given an array of integers, write a program to rotate the array in cyclic manner by one. Example: Int a [] = {1, 2, 3, 4, 5} Output:  {2, 3, 4, 5, 1}...

## 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...