我的歹马样例能过，提交上去就全WA，求神犇指点迷津。

#include<iostream>
#include<iomanip>
#include<limits>
using  namespace std;
int main(){
	void HYR();
	cout<<setprecision(4)<<fixed;
	int t(0);
	cin>>t;
	while(t--)
		HYR();
	return 0;
}
struct eq{
	double a;
	double b;
	double c;
	double f(double x){
		return a*x*x+b*x+c;
	}
};
int n(0);
eq a[int(2e2)]{};
void HYR(){
	double f(double);
	cin>>n;
	for(int i(1);i<=n;i++)
		cin>>a[i].a>>a[i].b>>a[i].c;
	double l(0);
	double r(1000);
	while(r-l>0.0000001){
		double m1(l+(r-l)/3);
		double m2(r-(r-l)/3);
		if(f(m1)>f(m2))
			l=m1;
		else
			r=m2;
	}
	cout<<f(l)<<'\n';
}
double f(double x){
	double ret(numeric_limits<double>::min());
	for(int i(1);i<=n;i++)
		ret=max(ret,a[i].f(x));
	return ret;
}