Question: Given an array, there is a largest element N. Check if that number is at least twice than all the other elements in the array. Return the index if it is, else return -1 Input: {3, 6, 1, 0} Output: -1 6 is the largest integer, and for every other number in the array x, 6 is… Read More »
Question: Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters. Input: “abccccdd” Output: 7 In the above example, the longest palindrome in the given string is “dccaccd” whose length is 7. A palindrome consists of letters with equal partners, plus possibly a unique… Read More »
Question: Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Output: 0 The easier method to find the cycle has been discussed in this post. This method is based upon the idea of a circular race track. If there is a slow runner and a fast runner, eventually the… Read More »
Question: Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Output: 0 We are given a linked list which may or may not have a loop. A loop in a linked list means that if we keep doing a next, we will never reach null. Thus, we can be… Read More »
Question: There is an array A[N] of N numbers. You have to compose an array Output[N] such that each element in Output[i] will tell the next greater element to the right in the original array. If there is no greater number to the right, then the output array should contain -1 in that position. Array 1: {4, 6,… Read More »
Question: Given an integer N, find all the prime factors of the number. Input: N = 45 Output: 3 5 Finding prime factors of any numbers is a very important concept in number theory. One sample problem is available here in which we have to find the largest prime factor. The mathematical concept behind this problem is simple.… Read More »
Question: Given an integer N, find the prime numbers in that range from 1 to N. Input: N = 25 Output: 2, 3, 5, 7, 11, 13, 17, 19, 23 We have several ways of finding prime numbers. Some of the methods are discussed in the these posts. Method 1 Method 2 Method 3 In this post we… Read More »
Question: Find the sum of even fibonacci numbers upto a limit N. Input:100 Output: 44 Fibonacci numbers are a miracle of Math and are defined as:- f(0) = 0 f(1) = 1 f(n) = f(n-1) + f(n-2); for n>=2 Thus the Fibonacci series can be given as 0, 1, 1, 2, 3, 5, 8, 13, 21… Let us… Read More »
Question: Given two strings, determine if they share a common sub-string. If they have a common sub-string, print YES else print NO. Input: studyalgorithms algos Output: 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 case String 1 =… Read More »
Question: If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below ‘N’ Input: N = 100 Output: 2318 The most naive approach to solve this problem… Read More »