A substring is the continuous sequence of the character from the given string which can be achieved by removing some character from the front and the end of the substring (possibly all or none). We are given a binary string and we have to find the length of the longest substring that contains at most X number zeros and Y number of ones where X and Y are given inputs. Sample Examples Input  string str = "101011"; int x = 1; int y = 2; Output The length of the longest substring with at most X zeroes and ... Read More

A binary string is a string that contains only two different types of characters in it which are '0' and '1'. Substrings are strings that are formed by deleting some character from the given string from the beginning and from the ending (possibly zero or all). We are given a string and we have to get all the substrings of it and take XOR of it. XOR is a bitwise operator that gives the result − if both the bits are the same then it will return zero otherwise 1. Input  string str = "10101" Output  XOR of all ... Read More

We are given two strings string A and string B along with an array that represents the cost to delete the ith character of the given string A. We need to delete some characters of string A (possibly zero or none) with the minimum cost such that no subsequence of A represents string B. We are going to see three approaches to implementing the code that is the recursive approach; the recursive and memoization approach; and tabulation or iterative dp. Example Let's have a look at the following example − Input string a = "xanxd" string b = ... Read More

Anagram of a string means a string contains exact same characters as another string with the order of characters may vary from the original string, so we called that both strings are anagram of each other. Here we have given the two strings first and second which are anagrams of each other. And our task is to minimize the count of operations to make the first string as second string. An operation is that we can delete an character from the begin or end of an first string and reinserting at any position. Sample Example Input  First: "hello", Second: "ohlle" ... Read More

A binary string is a string that contains only two types of different characters zeroes and ones. We can replace a substring '11' of the given string with another string '0' and we have to find the number of different possible strings we can get from it. We are going to use dynamic programming to get the solution as other methods may take exponential time complexity. Sample Example Input string str = 11010 Output 2 Explanation We can replace the first two numbers with the zero and can get another string 0010 and the second string is the ... Read More

Permutations and Combinations refer to the arrangements of objects in mathematics. Permutation − In permutation, the order matters. Hence, the arrangement of the objects in a particular order is called a permutation. Permutations are of two types − Permutation with repetition Suppose we have to make a three-digit code. Some possible numbers are 123, 897, 557, 333, 000, and 001. So how many numbers can we make like this? Let us look at it this way− In the once place, we have ten options − 0-9 Similarly, at the tenth and the hundredth place also, we have ten options. 0-9. ... Read More

HCF or the Highest common factor of two or more numbers refers to the highest number which divides them. A rational number is the quotient p/q of two numbers such that q is not equal to 0. Problem Statement Given an array with fractional numbers, find the HCF of the numbers. Example 1 Input [{4, 5}, {10, 12}, {24, 16}, {22, 13}] Output {2, 3120} Explanation The fractional numbers given are: 4/5, 10/12, 24/16 and 22/13 2/3120 is the largest number that divides all of them. Example 2 Input [{18, 20}, {15, 12}, {27, 12}, {20, 6}] ... Read More

The concept of an amicable pair of numbers or a friendly pair of numbers seems interesting right? So what exactly are amicable pairs of numbers? Two numbers are said to be an amicable pair of numbers only if the sum of the first number's proper divisors equals the sum of the second number's proper divisors. Also just in case you had forgotten, The Pythagoreans were always known for associating numbers with characteristics like justice and friendship. Problem Statement Implement a program to check whether the given pair of numbers is an amicable pair or not. ... Read More

The aim of this article is to implement a program to print the Stern-Brocot sequence. What is the Stern-Brocot sequence? Stern-Brocot sequence, which is also known as Stern’s diatomic series, is a sequence of numbers generated as given below. 1, 1, 2, 1, 3, 2, 3, 1, 4, 3, 5, 2, 5, 3, ... Although one may find that the Stern-Brocot sequence quite resembles the Fibonacci sequence 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ... The Stern-Brocot sequence differs from the Fibonacci sequence in the method the Fibonacci sequence is produced. In ... Read More

Prime numbers are those numbers that are greater than one and they simply have two factors: the number itself and factor 1. This indicates that no number apart from 1 as well as the number itself could be used to divide these numbers without leaving a residue. For instance, the first ten prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29. If we take the number 2, the factors are 2 and 1. That is the number itself and the factor 1. Similarly, if we take 11, the factors are 11 and 1. That is ... Read More