题解 | 买铅笔

#include <bits/stdc++.h>
using namespace std;

int main() {
  int n;
  cin >> n;
  int ans = INT_MAX;
  for (int i = 0; i < 3; i++){
    int num, price;
    cin >> num >> price;
    int buynum = (n + num - 1) / num;
    int cost = buynum * price;
    ans = min(ans, cost);
  }
  cout << ans << "\n";
  return 0;
}
// 64 位输出请用 printf("%lld")

向上取整 (n + num - 1) / num，可以理解为只要有余数就进１