# Array

Given a character matrix in which some of the cells have alphabets written on them while other cells are empty (empty cells contains character ‘-‘ in them). For example consider the below matrix: A – – – B – – – C All characters are unique. Set character on all empty cells in such a […]

Given a matrix of integers of order M*N and coordinates of a rectangular region in the matrix, write code to find the sum of all the elements in that rectangular region. For example, if the input matrix is And co-ordinated given are (3,4) and (6, 8), then they represent the below rectangular region whose Sum […]

Given a row (linear), two blocks are placed at each end and there are n empty positions between then. If ‘B’ represent block and n = 9 then the row looks like below: B _ _ _ _ _ _ _ _ _ B One blocks can be placed on each empty position. k blocks […]

Given a number N given in the form of array, with each index storing one digit of the number. Write code to change the number to the greatest number less than N, such that digits of that number are in non-decreasing order. For example: INPUT ARRAY: {1, 4, 3} (representing number 143) OUTPUT : 139 […]

Given a string of bits and a number k. In one flip, you can toggle k consecutive characters, how many flips are required to change the entire string to all ones. For example Input String: 0000110000 k: 3 OUTPUT: 4 Following are the four flips: FLIP-1: 1110110000 FLIP-2: 1110110111 FLIP-3: 1111000111 FLIP-4: 1111111111 If it is not possible […]

Given a string, print the variation of string as shown below Input String: ‘hat’ Replace one character with numeric one(‘1’): ‘1at‘, ‘h1t‘, ‘ha1‘ Replace two characters with ‘1’ each: ‘11t‘, ‘h11‘, ‘1a1‘ Replace three characters with ‘1’ each: ‘111‘ In all the strings above, wherever the numeric characters are consecutive, add them. So ’11t’ will become ‘2t’, Similarly ‘111’ […]

Given two arrays of integers, write a code to check if one is permutation (arranging the same numbers differently) of elements present in the other. For example, the below two arrays are permutations of each other: int a[5] = {1, 2, 3, 4, 5}; int b[5] = {2, 1, 4, 5, 3};

Given an array containing both positive and negative integers, write code to rearrange the elements so that positive and negative numbers comes alternately. If positive (or negative) integers is not equal in number then extra positive (or negative) numbers should come at the end of array. For example: Input : {1, 2, -2, -5, 6, […]

A better implementation of Stack is usually using linked list unless you are sure of the number of elements in array. But if you are just starting with data structures and are not familiar with linked list, you can try implementing stack in an array. While using array to implement stack is easy, it has limitation that […]

This video discusses the Linear Search algorithm in detail.