We are given an array of integer elements and the task is to calculate the count of sub-arrays that can be formed from the given array such that its elements can form a valid palindrome. Palindromes are the sequences that are arranged similarly from start and the end.Input − int arr[] = { 3, 3, 1, 4, 2, 1, 5}Output − Count of sub-arrays whose elements can be re-arranged to form palindromes are − 9Explanation − The valid sub-arrays whose elements can be arranged to form a palindrome are {3}, {3}, {1}, {4}, {2}, {1}, {5}, {1, 2, 1} and ... Read More

We are given two strings i.e. str1 and str2 and the task is to calculate the count of strings that can completely be generated from another string, but we can use one character once for forming the string. Like, we will take two strings str1 and str2 and check for the occurrence of str2 in str1 by using the character of str1 exactly once.Input − str_1 = "technical learning", str_2 = "learning"Output − Count of strings that can be formed from another string using each character at-most once are − 1Explanation − As we can see str_2 occurs in str_1 ... Read More

We are given an array of positive integers. The goal is to find the count of pairs of elements of arr[] such that pairs have elements ( p, q ) where p occurs in array for at least q times and q occurs in array for at-least p times.Let us understand with examples.Input − int arr[] = { 3, 3, 3, 5, 5, 6, 6}Output − Count of pairs in an array such that frequency of one is at least value of other are − 1Explanation − The valid pairs in an array where p occurs q times and q ... Read More

We are given an array of positive integers. The goal is to find the count of pairs of elements of arr[] such that pairs have elements ( A, B ) where frequency of A is B times and frequency of B is A.Let us understand with examples.Input − int arr[] = { 3, 3, 3, 5, 5, 6, 6}Output − Count of pairs in an array such that frequency of one is at least value of other are − 1Explanation − The valid pairs in an array where A occurs B times and B occurs A times are (3, 3) ... Read More

We are given a string of binary numbers i.e. combination of 0’s and 1’s and an integer value k and the task is to calculate the count of substrings formed with the given binary string having given k 1’s.Input − string str = ‘10000100000’, k = 2Output − Count of substrings of a binary string containing K ones are − 6Explanation − Substrings that can be formed from the given string are 1, 10, 100, 1000, 10000, 010, 100001, 10001, 1001, 101, 11, 1000010. So there are 6 substrings having k number of 1’s i.e. exactly 2 ones.Input − string ... Read More

We are given a string str[] and a number n. The goal is to find all substrings of str[] that have length n. If string is “abcde” and n=3 then substrings of length 3 are “abc”, “bcd”, “cde” and count is 3.Let us understand with examples.Input − str[] = “computer” n=4Output − Count of substrings of length n possible from the given string are − 5Explanation − Substrings with length 4 are: “comp”, “ompu”, ”mput”, “pute”, “uter”Input − str[] = “development” n=5Output − Count of substrings of length n possible from the given string are − 7Explanation − Substrings with ... Read More

We are given a string str[] and a character X. The goal is to find the substrings of str[] such that all the substrings contain X at least once. For str[]=”abc '' and X=’a’, the substrings containing ‘a’ at-least once are “a”, “ab”, “abc”. The count is 3.Let us understand with examples.Input − str[] = “aabccd” X=’c’Output − Count of sub-strings that contain character X at least once are − 14Explanation − Substrings containing at-least one ‘c’ will be : “c”, “c”, “bc”, “cc”, “cd”, “abc”, “bcc”, “ccd”, “aabc”, “abcc”, “bccd”, “aabcc”, “abccd”, “aabccd”.Input − str[] = “settings” X=’s’Output − ... Read More

We are given a string str[] containing ‘a’, ‘b’ and ‘c’ only. The goal is to find the substrings of str[] such that all the three characters are not part of that substring. For any string str, substrings could be “a”, “b”, “c”, “abb”, “bba”, “bc”, “ca”, “ccc” but not “abc”, “bcca” , “cab” as these have ‘a’, ‘b’ and ‘c’, all three.Let us understand with examples.Input − str[] = “aabc”Output − Count of sub-strings that do not contain all the characters from the set {‘a’, ‘b’, ‘c’} at the same time are − 8Explanation − Substrings will be : ... Read More

We are given an array arr[] containing integer elements and a variable k . The goal is to find the count of subarrays of arr[] that have greatest/maximum element more that k. If the array is [1, 2, 3] and k is 1. Then possible subarrays are [1], [2], [3], [1, 2], [2, 3], [1, 2, 3]. The subarrays with maximum element > 1 are [2], [3], [1, 2], [2, 3], [1, 2, 3]. So the count is 5.Let us understand with examplesInput − arr[] = {1, 2, 5, 3 } k=3Output − Count of subarrays whose maximum element is ... Read More

We are given a number n as input. The goal is to find values x such that condition (n xor x)=(nx) holds. Also x lies in range [0,n].Let us understand with examplesInput − n=10Output − Count of values of x