divisor summation
#include<iostream> using namespace std; int main() { int t; cin >> t; while (t--) { int n; cin >> n; int sum = 0; for (int i = 1; i * i <= n; i++) { if (n%i == 0) { sum += i; if (i != n/i) { sum += n / i; } } } cout << sum - n << endl; } return 0; }
Source: smart.ibsu.edu.ge