Error Curves HDU - 3714(三分)

Error Curves

#include <bits/stdc++.h>
#define eps 1e-10//就是这里一开始是1e-8一直WA，，，
#define INF -1e12
using namespace std;
int n;
double a[10010], b[10010], c[10010];
double cal(double x){double temp=INF;for(int i=0; i<n; i++){temp=max(temp, a[i]*x*x+b[i]*x+c[i]);}return temp;
}
int main(){int T;scanf("%d", &T);while(T--){scanf("%d", &n);for(int i=0; i<n; i++){scanf("%lf%lf%lf", &a[i], &b[i], &c[i]);}double l=0.0, r=1000.0;while(r-l>eps){double mid=l+(r-l)/3;double midd=r-(r-l)/3;if(cal(mid)>cal(midd)) l=mid;else r=midd;}printf("%.4lf\n", cal(l));}return 0;
}