[그리디] 백준 2839 설탕 배달 C++

 

https://www.acmicpc.net/problem/2839

2839번: 설탕 배달

#include<iostream>
#define INF 1234567891
using namespace std;

int n, ans, a;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);

    cin >> n;

    ans = INF;
    for (int i = 0; i < n / 5 + 1; i++) {
        a = n - 5 * i;
        if (a % 3 == 0) ans = min(ans, a / 3 + i);
    }

    if (ans == INF) ans = -1;
    cout << ans;
}