BOJ 3752 - 최대공약수 행렬식 [C++]

문제

링크

풀이

#include <iostream>
#define MOD 1000000007
using namespace std;
 
long long phi(int n) {
  long long ret = n;
  for (int i=2; i*i<=n; i++) {
    if (n % i) continue;
    ret -= ret / i;
    while (n % i == 0) n /= i;
  }
  if (n > 1) ret -= ret / n;
  return ret;
}
 
void solve(void) {
  int n; cin >> n;
 
  long long ans = 1;
  for (int i=0; i<n; i++) {
    int x; cin >> x;
    ans = (ans * phi(x)) % MOD;
  }
  cout << ans << "\n";
}
 
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
 
  int t; cin >> t;
  while (t--) solve();
  return 0;
}