g++编译
#include <iostream>//communication sys
#include   <iomanip>

int band = 2147483647;
int total = 0;
float de = 0.0000001;
using namespace std;
void  process(int *b,int *c, int m){//寻找单个设备的b/c的最大值，记录b-band和c-price
    float temp = 0.0;
    int bt,ct;
    for(int i = 0; i < m; i++){
        //cout<<temp<<b[i]*1.0/c[i];
        if(b[i]*1.0/c[i]>temp){
            temp = b[i]*1.0/c[i];
            bt = b[i];
            ct = c[i];
        }
        else if(b[i]*1.0/c[i]<temp+de&&b[i]*1.0/c[i]>temp-de&&b[i]<bt){//比值相同时去较小的band
            temp = b[i]*1.0/c[i];
            bt = b[i];
            ct = c[i];
        }
    }
    if(bt<band) band = bt;
    total +=ct;
}

int main()
{
    int t;
    int n;
    int m;
    float maxbc[10];

    cin >> t;
    for(int i = 0; i < t; i++){
        cin >> n;
        for(int j = 0; j < n; j++){
            cin >> m;
            int b[m],c[m];
            for(int k = 0; k < m; k++)cin >> b[k] >> c[k];
            process(b,c,m);//一个设备处理一次
        }
        maxbc[i] = band*1.0/total;
        band = 2147483647;
        total = 0;
    }

    for(int s =0; s < t; s++)
    cout <<fixed <<setprecision(3)<< maxbc[s]   <<endl;
    return 0;
}