网易2017秋招编程题6

买苹果：

#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    int n;
    cin >> n;
    if (n < 6 || n == 7) cout << -1 << endl;
    else {
        int n8 = n / 8, n6 ;

        if (n % 8 == 0) n6 = 0;
        else n6 = 1;

        while ( n8 * 8 + n6 * 6 > n) {
            --n8;
            ++n6;
        }

        if (n8 * 8 + n6 * 6 == n) cout << n6 + n8 << endl;
        else cout << -1 << endl;
    }

    return 0;
}