1797:金银岛

1797:金银岛

#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<queue>
#include<stack>
#include<cstring>
using namespace std;
int k;
int shubao,zhonglei;
struct haosicheng{
    int zongjiazhi,zongzhiliang;
    double danjia;
}item[500];
double mycomp(const haosicheng &a,const haosicheng &b)
{
    return a.danjia>b.danjia;
}
void init()
{
    int k;
    scanf("%d",&k);
    for(int i=1;i<=k;i++)
    {
        scanf("%d",&shubao);
        scanf("%d",&zhonglei);
        for(int j=1;j<=zhonglei;j++)
        {
            scanf("%d%d",&item[j].zongzhiliang,&item[j].zongjiazhi);
            item[j].danjia=(double)item[j].zongjiazhi/(double)item[j].zongzhiliang;
        }
        sort(item+1,item+(zhonglei+1),mycomp);
        double worth=0;
        for(int i=1;i<=zhonglei;i++)
        {
            if(shubao>=item[i].zongzhiliang)
            {
                worth=worth+item[i].danjia*item[i].zongzhiliang;
                shubao=shubao-item[i].zongzhiliang;
            }
            else
            {
                worth=worth+item[i].danjia*shubao;
                shubao=shubao-shubao;
            }
            
        }
        printf("%.2lf\n", worth);
    }
}
int main()
{
    init();
    return 0;
}