题解 | #网购#

#include <stdlib.h>

int main() {
    double a = 0.0;
    int b, c, d;
    b = c = d = 0;
    scanf("%lf %d %d %d", &a, &b, &c, &d);
    if (b == 11 && c == 11)
    {
        a *= 0.7;
    }
    else if (b == 12 && c == 12)
    {
        a *= 0.8;
    }
    a -= d * 50;
    if (a <= 0)
        a = 0;
    printf("%.2lf", a);
    return 0;
}