C++ 알고리즘 - 백준 2839 설탕 배달

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

 

#include <iostream>
#define endl "\n"

using namespace std;

int main(void) {
	// C++ Init
	ios::sync_with_stdio(false);
	cin.tie(NULL);

	int input;
	int box5, box3;
	int answer;
	int count;

	cin >> input;
	box5 = input / 5;

	while (true) {
		count = input - (box5 * 5);

		if (count % 3 == 0) {
			box3 = count / 3;
			cout << box5 + box3;
			break;
		}

		else {
			box5--;
		}

		if (box5 == -1) {
			cout << -1;
			break;
		}
	}
}