#include<stdio.h>
#include<algorithm>
using namespace std;
const int maxn = 1000;
typedef struct yuebing {
    double cun;
    double shouyi;
    double danjian;
}yue;
yue arr[maxn];
bool cmp(yue a, yue b) {
    return a.danjian>b.danjian;
}
int main()
{
    int N, D; double shoushou = 0;
    scanf("%d%d", &N, &D);
    //輸入庫存
    for (int i = 0; i<N; i++) {
        scanf("%lf", &arr[i].cun);
    }
    //輸入收益，並計算單收益
    for (int i = 0; i<N; i++) {
        scanf("%lf", &arr[i].shouyi);
        arr[i].danjian = arr[i].shouyi / arr[i].cun;
    }
    sort(arr, arr + N, cmp);//根據但收益排序
    for (int i = 0; i<N; i++) {
        if (arr[i].cun >= D) {
            shoushou += arr[i].danjian*D;
            break;
        }
        if (arr[i].cun<D)
            shoushou += arr[i].shouyi;
        D -= arr[i].cun;
    }
    printf("%.2f", shoushou);
    return 0;
}
 

【PAT】B1020 月餅 (25)（25 分）