# HackerEarth Modulo Strength problem solution

In this HackerEarth Modulo Strength problem solution Alice is the teacher of a class having N students, where each student is having some personality value, given in the form of an array A. Here Ai denotes the personality value of ith student, where 1 <= i <= N. Alice has a special integer K with her. Student i is a friend of Student j, if and only if (A[i] % K) = (A[j] % K). Each student's strength is equal to the number of friends he/she has. Alice needs to calculate the sum of the strength of all the students in the class. Help Alice for the same.

## HackerEarth Modulo Strength problem solution.

`#include<stdio.h>int main(){int n,k;long long int *arr,strength=0,*res;scanf("%d",&n);scanf("%d",&k); arr = (long long int *) malloc( n * sizeof(long long int ));res = (long long int *) malloc( k * sizeof( long long int ));for(int i = 0 ; i<n ; i++){scanf("%lld",&arr[i]);}for(int i = 0 ; i< n ; i++){int loc = arr[i] % k;res[loc] = res[loc] + 1;} for(int i = 0 ; i<k ; i++ ){if(res[i] == 0 || res[i] == 1)continue;strength = strength + ( res[i] * (res[i] - 1) ) ;}printf("%lld",strength);  return 0;}`