#include <stdio.h>int main(){puts("转载请注明出处[vmurder]谢谢");puts("网址：blog.csdn.net/vmurder/article/details/43526909");}
！！！其实我脸一点也不黑！我天天洗脸的！
题解：
我的姿势是先模拟退火，，然后少少爬下山来取优。
参数什么的看代码就好。
那个种子的生成方式是[生日^名字首字母的hash]
代码：
#include <cmath>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define N 10100#define inf 23333333333333333ll#define eps 1e-3#define down 0.993using namespace std;double ln,rn,lm,rm;struct Point // 点{double x,y,z; // 坐标、该点作为结束点的答案。Point(double _x=0.0,double _y=0.0):x(_x),y(_y){}bool in(){if(x<ln||x>rn)return 0;if(y<lm||y>rm)return 0;return 1;}}P[N],now,ans;int p;inline double Rand(){return ((double)(rand()%1000+1.0))/1000.0;}inline void init(){double tempx=0.0,tempy=0.0;for(int i=1;i<=p;i++){tempx+=P[i].x,tempy+=P[i].y;ln=min(P[i].x,ln),rn=max(P[i].x,rn);lm=min(P[i].y,lm),rm=max(P[i].y,rm);}now=Point(tempx/p,tempy/p);ans.z=inf;}inline double calc(const Point &a,const Point &b){return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));}inline double Calc(Point &a){a.z=0.0;for(int i=1;i<=p;i++)a.z+=calc(P[i],a)*P[i].z;if(a.z<ans.z)ans=a;return a.z;}Point newpos(double T,const Point &a){double alp=2.0*acos(-1.0)*Rand();return Point(a.x+T*cos(alp)*Rand(),a.y+T*sin(alp)*Rand());}void Std_Anne(double T=sqrt((rn-ln)*(rn-ln)+(rm-lm)*(rm-lm))*0.3){for(;T>eps;T*=down){Point next=newpos(T,now);if(next.in()){double dis=Calc(now)-Calc(next);if(exp(dis/T)>=Rand())now=next;}}}void ioi(){for(int i=1;i<=1000;i++){Point next=newpos(0.001,ans);if(next.in()){double dis=Calc(next)-Calc(now);if(dis>0)now=next;}}}int main(){freopen("test.in","r",stdin);srand(20134858);scanf("%d",&p);for(int i=1;i<=p;i++)scanf("%lf%lf%lf",&P[i].x,&P[i].y,&P[i].z);init();Std_Anne(1000000.0);ioi();printf("%.3lf %.3lf\n",ans.x,ans.y);return 0;}
我们摇摇头说，困难其实没什么大不了。
