BOJ 2526 - 싸이클 [C++]

문제

링크

풀이

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
 
void solve(void) {
  int n, p; cin >> n >> p;
 
  vector<int> cnt(p, 0);
  int cur = n;
  while (cnt[cur] < 2) {
    cnt[cur]++;
    cur = (cur * n) % p;
  }
  cout << count(cnt.begin(), cnt.end(), 2);
}
 
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
 
  solve();
  return 0;
}