BOJ 34367 - Cookie Monster Concussion [C++]

문제

링크

풀이

#include <iostream>
using namespace std;
 
inline long long calc(long long c) {
  long long ret = 0;
  while (c) ret += c % 10, c /= 10;
  return ret;
}
 
void solve(void) {
  long long c; cin >> c;
 
  while (c > 9) c = calc(c);
  cout << c;
}
 
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
 
  solve();
  return 0;
}