poj 3301 Texas Trip 夜

http://poj.org/problem?id=3301

都说这个题是三分题目 但它不是单峰吧 好怀疑 

我根据网上的代码写的  连第二组数据都过不了 但交上去 0ms 过啦

建议不要做这道题 如果有高手指点 那就跟好了

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<set>
#include<cmath>
#include<algorithm>

using namespace std;

const int N=1005;
const double M=1000000.0;
const double PI=acos(-1.0);
const double eps=1e-10;
int x[N];
int y[N];
double sidemax(double k,int n)
{
    double x1,x2,y1,y2;
    x1=y1=M;
    x2=y2=-M;
    double xtemp,ytemp;
    for(int i=0;i<n;++i)
    {
        xtemp=x[i]*cos(k)-y[i]*sin(k);
        ytemp=y[i]*cos(k)+x[i]*sin(k);
        //cout<<xtemp<<" "<<ytemp<<endl;
        x1=min(x1,xtemp);
        x2=max(x2,xtemp);
        y1=min(y1,ytemp);
        y2=max(y2,ytemp);
    }
    //cout<<x1<<" "<<x2<<endl;
    return max(y2-y1,x2-x1);
}
int main()
{
    //freopen("data.txt","r",stdin);
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int n;
        scanf("%d",&n);
        for(int i=0;i<n;++i)
        scanf("%d %d",&x[i],&y[i]);
        double l=0.0;
        double r=PI/2.0;
        //int I=0;
        while((r-l)>eps)
        {
            //cout<<++I<<endl;
            //cout<<l<<" TTTT "<<r<<endl;
            double mid=(r+l)/2.0;
            double midr=(mid+r)/2.0;
            if(sidemax(mid,n)<sidemax(midr,n))
            {
                r=midr;
            }else
            {
                l=mid;
            }
        }
        printf("%.2f\n",sidemax(l,n)*sidemax(l,n));

    }
    return 0;
}