题解 | 游游的水果大礼包

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

int main() {
    int n, m, a, b;
    cin >> n >> m >> a >> b;
    int max_a = n / 2 < m ? n/2 : m;
    long long max_val = 0;
    for(int i = max_a; i >= 0; i--) {
        int now_apple = n - 2 * i;
        int now_peach = m - i;
        int num_b = now_apple < now_peach / 2 ? now_apple : now_peach / 2;
        max_val = fmax(max_val, (long long)i * a + (long long)num_b * b);
    }
    cout << max_val << endl;
}
// 64 位输出请用 printf("%lld")