链接

思路

交了好多发，都是wrong

初始值取平均数就1A了

真的是玄学的算法

代码

// luogu-judger-enable-o2#include 
    
     using namespace std;const double eps=1e-15;int read() {    int x=0,f=1;char s=getchar();    for(;s>'9'||s<'0';s=getchar()) if(s=='-') f=-1;    for(;s>='0'&&s<='9';s=getchar()) x=x*10+s-'0';    return x*f;}struct node {    double x,y,w;}e[1007];double n,ansx,ansy;double dis(int a,double x_,double y_) {    return sqrt((e[a].x-x_)*(e[a].x-x_)+(e[a].y-y_)*(e[a].y-y_));}double calc(double x,double y) {    double ans=0;    for(int i=1;i<=n;++i)        ans+=dis(i,x,y)*e[i].w;    return ans;}void mnth() {    double T=3000;    while(T>eps) {        double nowx=ansx+(rand()*2-RAND_MAX)*T;        double nowy=ansy+(rand()*2-RAND_MAX)*T;        double delta=calc(nowx,nowy)-calc(ansx,ansy);        // cout<
     
      <<" "<
      
       <<"\n";        if(delta<0) {            ansx=nowx,ansy=nowy;        } else if(exp(-delta/T)*RAND_MAX>rand()) {            ansx=nowx,ansy=nowy;        }        T*=0.996;    }}int main() {    // freopen("a.in","r",stdin);    srand(time(NULL));    n=read();    for(int i=1;i<=n;++i) {        e[i].x=read(),e[i].y=read(),e[i].w=read();        ansx+=e[i].x;        ansy+=e[i].y;    }    ansx/=n;    ansy/=n;    mnth();    mnth();    mnth();    mnth();    printf("%.3f %.3f\n",ansx,ansy);    return 0;}