1018 Communication System

#include <fstream.h> 
#include <search.h> 
#include <iomanip.h> 
#define in cin 

struct BP{ 
    int b; 
    int p; 
}; 

BP my[100][100]; 
int n,m; 
int len[100]; 
int blen; 
int bs[10001]; 

int compare(const void* a,const void *b){ 
    return (*(BP*)a).b-(*(BP*)b).b; 
} 

int comp(const void* a,const void *b){ 
    return (*(int*)a)-(*(int*)b); 
} 

void getData(){ 
    int i,j,k; 
    in>>m; 
    for(i=0;i<m;i++){ 
        in>>len[i]; 
        for(j=0;j<len[i];j++) 
            in>>my[i][j].b>>my[i][j].p; 
        qsort(my[i],len[i],sizeof(BP),compare); 
    } 
    bs[0]=0;k=0;blen=1; 
    for(i=0;i<m;i++) 
        for(j=0;j<len[i];j++) 
            bs[blen++]=my[i][j].b; 
    qsort(bs,blen,sizeof(int),comp); 
} 

int getIndex(int row,int t){ 
    int back=25535; 
    for(int i=0;i<len[row];i++) 
        if(my[row][i].b>=t&&my[row][i].p<back) 
            back=my[row][i].p; 
    return back; 
} 
void solve(){ 
    int i,j; 
    double total; 
    double max=-1; 
    for(i=1;i<blen;i++){ 
        if(bs[i]==bs[i-1])continue; 
        total=0; 
        for(j=0;j<m;j++){ 
            int s=getIndex(j,bs[i]); 
            if(s<0) 
                break; 
            total+=s; 
        } 
        if(j<m)continue; 
        if(max<bs[i]/total) 
            max=bs[i]/total; 
    } 
    cout<<setiosflags(ios::fixed)<<setprecision(3)<<max<<endl; 
} 
void main() 
{ 
    in>>n; 
    for(int i=0;i<n;i++){ 
        getData(); 
        solve(); 
    } 
}