A queue is a linear data structure which maintains the order in which the elements appear. You need to implement a queue, using two stacks such that it behaves in the same way. If you are unfamiliar with the queue data structure and the stack data structure, it would be a good idea to learn them before approaching this problem. Problem Statement: The basic crux of the problem is that you are to implement a queue and its operations using stacks. It may seem unnecessary in the beginning, as a…
Hackerrank


Question: Given a string, Sherlock considers it valid if all the characters in the string occur the same number of time. However, a string is also valid if the frequencies are same after removing any one character. Example 1:Input: str = “aabbcd”Output: NO Example 2:Input: str = “abcc”Output: YES Problem Statement: Let us try to simplify the problem statement first. Sherlock needs to verify if a given string is valid. A string is valid under 2 conditions: All characters of the string appear the same number of times. If you…

Question: Given two strings, determine if they share a common substring. Input: “a” and “art” Output: YES Problem Statement Let me try to simplify this problem statement first. You are given two strings, and you need to find out if they share a common substring or not. If you can find a common substring, output “YES”, else output “NO”. Note that you don’t have to find out what is the common substring. Another important aspect of this problem is that the substring can be as small as 1 character. A…

Question: You will be given two arrays of integers and asked to determine all integers between two sets that satisfy the following two conditions:– The elements of the first array are all factors of the integer being considered– The integer being considered is a factor of all elements of the second array Input:a = { 2, 6 }b = { 24, 36 } Output:2 I really want to simplify this really confusing problem statement first. The hardest part about this problem is to understand what is it actually saying. To…

Question: Given an array of integers, find the number of pairs of array elements that have a difference equal to the target value. Example: Input:arr[ ] = {1, 2, 3, 4}k = 1 Output: 3 Problem Statement Let us try to simplify the problem statement first and understand the sample test case. You are given an array of unique integers which is in any random order. Along with the array, you are also given a target value k. If you pick up any 2 integers from the array, they would…

Question: You are required to find missing numbers that are left out while an artist transports numbers from one array to other. The output array should be sorted. Input:arr [ ] = {7, 2, 5, 3, 5, 3}brr [ ] = {7, 2, 5, 4, 6, 3, 5, 3} Output:Missing numbers: {4, 6} Problem Statement: Let me try to simplify the problem a little first. The problem description is quite verbose and we narrow down it to quite an extent. To summarize, the artist has an original array brr, and…

Question: Given 3 arrays, where each element represent the height of a cylinder. Find the maximum possible height of equal stacks by removing one or more cylinders from the original stack. Example: Input: n1[] = {3, 2, 1, 1, 1}n2[] = {4, 3, 2}n3[] = {1, 1, 4, 1} Output: 5 Problem Statement Let us try to simplify the problem statement first. The problem states that you are provided with 3 sets of arrays. Each element in the array represents the height of a cylinder. Now, all these cylinders are…

Question: You are given an array of integers. After a left rotation of k times, find the resultant array. Example 1:Input: arr [ ] = {1, 2, 3, 4, 5}, size = 5, k = 2Output: {3, 4, 5, 1, 2} Example 2:Input: arr [ ] = {4, 8, 15, 16, 23, 42}, size = 6, k = 12Output: {4, 8, 15, 16, 23, 42} Terminology: To understand rotation of an array, you can assume that the array is kind of on an infinite conveyor belt, that keeps on looping.…

Question: Find the sum of even fibonacci numbers upto a limit N. Input:100Output: 44 Fibonacci numbers are a miracle of Math and are defined as: Thus the Fibonacci series can be given as0, 1, 1, 2, 3, 5, 8, 13, 21… Let us try to understand the question. We need to find all the Fibonacci numbers till a limit ‘N’ and then sum only the even numbers in them.Example:N = 10 Fibonacci numbers: 0, 1, 1, 2, 3, 5, 8 Sum of even numbers: 2 + 8 = 10 N…

Question: Given two strings, determine if they share a common substring. If they have a common substring, print YES else print NO. Input:studyalgorithmsalgosOutput: YES This is one of the easy problems but can get a little tricky, if we do not understand it completely. Let us try to understand the test caseString 1 = “studyalgorithms” String 2 = “algos”The substring “algo” is common between both the substrings and therefore the answer is “YES“. Let us try to take one more test case. String 1 = “hello” String 2 = “world”The…
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