Rice PROG-1030

#include<stdio.h>
#include<algorithm>
using namespace std;

typedef struct{
    double price;
    double quantity;
    double ppq;
}rice;

bool mycmp(rice a,rice b){
    return a.ppq < b.ppq;
}

int main()
{
    int k;
    scanf("%d",&k);
    rice arrice[k];
    for(int i=0;i<k;i++){
        scanf("%lf %lf",&arrice[i].price,&arrice[i].quantity);
        arrice[i].ppq = arrice[i].price/arrice[i].quantity;
    }
    sort(arrice,arrice+k,mycmp);
    int m;
    scanf("%d",&m);
    int j = 0;
    for(int i=0;i<m;i++){
        double x;
        double ans = 0;
        scanf("%lf",&x);
        while(x > 0){
            if(arrice[j].quantity >= x){
                ans += arrice[j].ppq*x;
                arrice[j].quantity -= x;
                x = 0;
            }else{
                ans += arrice[j].ppq*arrice[j].quantity;
                x -= arrice[j].quantity;
                arrice[j].quantity = 0;
            }
            if(arrice[j].quantity == 0){
                j++;
            }
        }
        printf("%.3lf\n",ans);
    }
}