九十分代码

17,19TLE

玄关求条

#include <bits/stdc++.h>

using namespace std;

int n;
double p,a[100050],b[100050],l,r,esp=1e-6;

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>p;
    for(int i=1;i<=n;i++)cin>>a[i]>>b[i];
    l=0,r=1e15;
    while(r-l>esp)
    {
        double mid=(l+r)/2;
        double res=0;
        for(int i=1;i<=n;i++)
        {
            res+=min(b[i]-a[i]*mid,0.0);
        }
        if(res+p*mid>=0)l=mid;
        else r=mid;
    }
    if(r==1e15)cout<<-1<<endl;
    else printf("%.10lf",r);
    return 0;
}