Suppose we have an array of n elements called A. We have another number k. Our task is to find last k digits of the product of elements in the array A. Suppose the A = [15, 22, 13, 19, 17], then the product is 1385670, the last k = 3 digits are 670.To solve this problem, we will multiply the numbers under modulo 10k.Example Live Demo#include #include using namespace std; int displayLastKNumbers(int array[], int n, int k) {    int mod = (int)pow(10, k);    int mul = array[0] % mod;    for (int i = 1; i < n; ... Read More

Suppose we have a set of integers. We have to find a number ‘d’, where d = a + b + c, and we have to maximize (a + b + c), all a, b, c, and d are present in the set. The set will hold at least one element, and at max 1000 elements. Each element will be a finite number. If the set is {2, 3, 5, 7, 12}, then 12 is largest d. this can be represented by 2 + 3 + 7To solve this problem, we can use the hashing technique. We will store the ... Read More

Suppose we have two numbers N and K. The task is to print K numbers, which are the power of 2 and their sum is N. If it is not possible, then return -1. Suppose N = 9 and K = 4, then the output will be 4 2 2 1, whose sum is 9, and a number of elements is 4, and each of them is a power of 2.We have to follow these steps to solve this problem −If k is less than the number of set bits in N or more than the number N, then return ... Read More

Suppose, we have N intervals in the form {L, R}, the L is the starting time, and R is the ending time. We have to find an intersection of all intervals. An intersection is an interval that lies within all of the given intervals. If no such found, return -1. For example, if the intervals are like [{1, 6}, {2, 8}, {3, 10}, {5, 8}, The output interval is {5, 6}To solve this problem, we will follow these steps −Consider the first interval is the final intervalStarting from the second interval, try searching for the intersection. Two cases can be ... Read More

Suppose we have string str, and another substring sub_str, we have to find the indices for all occurrences of the sub_str in str. Suppose the str is “aabbababaabbbabbaaabba”, and sub_str is “abb”, then the indices will be 1 9 13 18.To solve this problem, we can use the substr() function in C++ STL. This function takes the initial position from where it will start checking, and the length of the substring, if that is the same as the sub_str, then returns the position.Example Live Demo#include using namespace std; void substrPosition(string str, string sub_str) {    bool flag = false;    for ... Read More

Suppose we have three integers a, b and c. Suppose in an infinite sequence, a is the first term, and c is a common difference. We have to check whether b is present in the sequence or not. Suppose the values are like a = 1, b = 7 and c = 3, Then the sequence will be 1, 4, 7, 10, …, so 7 is present in the sequence, so the output will be ‘yes’.To solve this problem, we have to follow these two steps −When c = 0, and a = b, then print yes, and if a ... Read More

Consider we have an expression exp, and we have to check whether the exp has a duplicate set of parentheses around it or not. An expression will have duplicate parentheses if one sub-expression will be surrounded by more than one parentheses set. For example, if the expression is like −(5+((7−3)))Here the sub-expression (7 – 3) is surrounded by two parentheses pair, so these are duplicate parentheses.To solve this problem, we will use stacks. We will iterate through each character in the exp, and if the character is opening parentheses ‘(’, or any of the operator or operand, then push it ... Read More

Suppose we have a string s, and another array of strings A. We have to find whether the array is containing a string with the one-character difference from the current string of different lengths. Suppose the string is like “banana”, and the array looks like [“bana”, “orange”, “banaba”, “banapy”], the result will be true, as there is one string banaba, here only one character is different than a banana.To solve this problem, we will follow some steps −Traverse through given string s, and check for every string in the array, then follow these steps for every string in arr −Check ... Read More

We have to find the GCD of two numbers of which one number can be as big as (109 ^ 109), which cannot be stored in some data types like long or any other. So if the numbers are a = 10248585, n = 1000000, b = 12564, then result of GCD(a^n, b) will be 9.As the numbers are very long, we cannot use the Euclidean algorithm. We have to use the modular exponentiation with O(log n) complexity.Example Live Demo#include #include using namespace std; long long power(long long a, long long n, long long b) {    long long res = ... Read More

Suppose we have an array of integers. The array is A, and the size is n. Our task is to find the frequency of all elements in the array less than O(n) time. The size of the elements must be less than one value say M. Here we will use the binary search approach. Here we will recursively divide the array into two parts if the end elements are different, if both its end elements are the same, it means all elements in the array are the same as the array is already sorted.Example Live Demo#include #include using namespace std; void ... Read More