题目大意：给定长轴与x轴的夹角以及长轴与短轴的比值，求最小椭圆覆盖
把坐标变换一下，转化成最小圆覆盖
然后就是随机增量法了= =
【别问我这算法是咋回事】
#include <cmath>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define M 50500#define EPS 1e-7#define PI 3.1415926535897932using namespace std;struct Point{double x,y;Point() {}Point(double _,double __):x(_),y(__) {}friend istream& operator >> (istream &_,Point &p){scanf("%lf%lf",&p.x,&p.y);return _;}friend Point operator + (const Point &p1,const Point &p2){return Point(p1.x+p2.x,p1.y+p2.y);}friend Point operator – (const Point &p1,const Point &p2){return Point(p1.x-p2.x,p1.y-p2.y);}friend Point operator * (const Point &p,double rate){return Point(p.x*rate,p.y*rate);}friend double operator * (const Point &p1,const Point &p2){return p1.x*p2.y – p1.y*p2.x;}friend Point Rotate(const Point &p,double alpha){return Point( p.x * cos(alpha) – p.y * sin(alpha) , p.x * sin(alpha) + p.y * cos(alpha) );}friend double Distance(const Point &p1,const Point &p2){return sqrt( (p1.x-p2.x)*(p1.x-p2.x) + (p1.y-p2.y)*(p1.y-p2.y) );}}points[M];struct Line{Point p,v;Line() {}Line(const Point &_,const Point &__):p(_),v(__) {}};struct Circle{Point o;double r;Circle() {}Circle(const Point &_,double __):o(_),r(__) {}bool In_Circle(const Point &p){return Distance(o,p)<r+EPS;}}ans;int n,a,p;Point Get_Intersection(const Line &l1,const Line &l2){Point u=l1.p-l2.p;double temp=(l2.v*u)/(l1.v*l2.v);return l1.p+l1.v*temp;}int main(){srand(19980402);int i,j,k;cin>>n;for(i=1;i<=n;i++)cin>>points[i];cin>>a>>p;double alpha=-a/180.0*PI;for(i=1;i<=n;i++){points[i]=Rotate(points[i],alpha);points[i].x/=p;}random_shuffle(points+1,points+n+1);for(i=1;i<=n;i++)if(!ans.In_Circle(points[i])){ans=Circle(points[i],0);for(j=1;j<i;j++)if(!ans.In_Circle(points[j])){ans=Circle((points[i]+points[j])*0.5,Distance(points[i],points[j])/2);for(k=1;k<j;k++)if(!ans.In_Circle(points[k])){Line l1((points[i]+points[j])*0.5,Rotate(points[i]-points[j],PI/2));Line l2((points[i]+points[k])*0.5,Rotate(points[i]-points[k],PI/2));Point p=Get_Intersection(l1,l2);ans=Circle(p,Distance(p,points[i]));}}}printf("%.3lf\n",ans.r);return 0;}
，感悟了不同的人生。凌晨，随着滑轮接触地面，
