# Category: Intermediate

## 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...

## Find median of two sorted arrays of same size

Objective:  Given two sorted arrays of size n. Write an algorithm to find the median of combined array (merger of both the given arrays, size = 2n). What is Median? The median is the value separating the...

## Find local minimum or local maximum in O(1).

Objec­tive: Given an array such that every next element differs from the previous by +/- 1. (i.e. a[i+1] = a[i] +/-1 ) Find the local max OR min in O(1) time. The interviewer mentioned one...

## 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...

## Find the local minima in a given array

Objec­tive:  Given an array of integer write an algorithm to find the local minima. Local Minima: An element is considered as local minima if it is less than both of its neighbors (if neighbors exist)....

## Maximum Subarray OR Largest Sum Contiguous Subarray Problem – Divide and Conquer

Objec­tive:  The max­i­mum sub­ar­ray prob­lem is the task of find­ing the con­tigu­ous sub­ar­ray within a one-dimensional array of num­bers which has the largest sum. Exam­ple: int [] A = {−2, 1, −3, 4, −1, 2, 1, −5, 4}; Output:...

## Maximum difference between two elements where larger element appears after the smaller element

Objective: Given an array A[], write an algorithm to find Maximum difference between two elements where larger element appears after the smaller element or in other words find A[i] and A[j] such that A[j]-A[i]...

## Find the two repeating elements in a given array | 6 Approaches

Objective: Given an array of n+2 elements. All elements of the array are in range 1 to n and all elements occur once except two numbers which occur twice. Write an algorithm to find...

## Find two elements whose sum is closest to zero

Objective: Given an array of positive and negative integers, write a algorithm to find the two elements such their sum is closest to zero. Example: int a [] = {1, 4, -5, 3, -2,...

## Find the element which appears maximum number of times in the array.

Objective: Given an array of integers, write a algorithm to find the element which appears maximum number of times in the array. Example: int [] arrA = {4, 1, 5, 2, 1, 5, 9,...

## Find duplicates in an given array in O(n) time and O(1) extra space.

Objective: Given an array of integers, find out duplicates in it. Example: int [] a = {4, 6, 2, 1, 2, 5}; Output: Array has duplicates : 2 int a [] = {1, 6,...

## Find longest Snake sequence in a given matrix

Objective: Given two dimensional matrix, write an algorithm to find out the snake sequence which has the maximum length. There could be many snake sequence in the matrix, you need to return the one...

## Dynamic Programming – Count all paths in 2D Matrix with Obstructions in it

Objective: Given two dimensional matrix, write an algorithm to count all possible paths from top left corner to bottom-right corner. You are allowed to move only in two directions, move right OR move down....

## Dynamic Programming – Count all paths from top left to bottom right of a mXn matrix

Objective: Given two dimensional matrix, write an algorithm to count all possible paths from top left corner to bottom-right corner. You are allowed to move only in two directions, move right OR move down....

## Print All Diagonals of a given matrix

Objective: Given two dimensional matrix, write an algorithm to print all the diagonals of matrix. Example: Approach: We will solve this problem in two parts. first half of diagonals and second half of diagonals....