GCD 합

#include <iostream> #include <vector> #include <algorithm> using namespace std; int gcd(int a, int b) { if (b == 0) return a; return gcd(b, a % b); } int main(void) { int t; int n; vector<int> v; long long answer; ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); cin >> t; for (int i = 0; i < t; i++) { cin >> n; v.resize(n); answer = 0; for (int j = 0; j < n; j++) cin >> v[j]; sort(v.begin(), v.end(), greater<>()); for (int j = 0; j < n; j++) { for (int k = j + 1; k < n; k++) { answer += gcd(v[j], v[k]); } } cout << answer << "\n"; } return (0); }