HDU 1700 Points on Cycle(向量旋转)

题目链接

水题，卡了下下精度。

 #include <cstdio>
 #include <iostream>
 #include <cmath>
 using namespace std ;
 #define PI acos(-1.0)
 #define eps 1e-8
 int judge(double x,double y)
 {
     double a;
     a = x-y;
     if(a < )
         a = -a;
     if(a < eps)
         return ;
     else
         return ;
 }
 int main()
 {
     double x,y,lx,rx,ly,ry,a;
     int t;
     scanf("%d",&t);
     while(t--)
     {
         scanf("%lf%lf",&x,&y);
         a = PI/*;
         lx=x*cos(a)-y*sin(a);
         ly=x*sin(a)+y*cos(a);
         rx=x*cos(a)+y*sin(a);
         ry=-x*sin(a)+y*cos(a);
         if(ly - ry > eps)
         {
             swap(ly,ry);
             swap(lx,rx);
         }
         else if(judge(ly,ry))
         {
             if(lx - rx > eps)
             {
                 swap(ly,ry);
                 swap(lx,rx);
             }
         }
         printf("%.3lf %.3lf %.3lf %.3lf\n",lx,ly,rx,ry);
     }
     return ;
 }