POJ 2420 A Star not a Tree?(模拟退火)

题目链接

居然1Y了，以前写的模拟退火很靠谱啊。

 #include <cstdio>
 #include <cstring>
 #include <string>
 #include <cmath>
 #include <ctime>
 #include <cstdlib>
 #include <iostream>
 using namespace std;
 struct point
 {
     double x,y;
 }p[];
 int n;
 int a[] = {,,-,};
 int b[] = {,-,,};
 double dis(double x1,double y1,double x2,double y2)
 {
     return sqrt((x1-x2)*(x1-x2)+(y2-y1)*(y2-y1));
 }
 double fun(double x,double y)
 {
     double ans = ;
     int i;
     for(i = ;i < n;i ++)
     {
         ans += dis(p[i].x,p[i].y,x,y);
     }
     return ans;
 }
 int main()
 {
     int T,i,key,num,j,k;
     double tx,ty,ans,d,x,y;
     srand(time(NULL));
     scanf("%d",&n);
     for(i = ;i < n;i ++)
     {
         scanf("%lf%lf",&p[i].x,&p[i].y);
     }
     key = ;
     ans = ;
     num = ;
     x = p[].x;
     y = p[].y;
     T = ;
     while(T--)
     {
         for(i = ;i <= num;i ++)
         {
             for(j = ;j < ;j ++)
             {
                 k = rand()%key;
                 tx = x + k*a[j]*T;
                 ty = y + k*b[j]*T;
                 if(tx >= &&tx <= &&ty >= &&ty <= )
                 {
                     d = fun(tx,ty);
                     if(ans > d)
                     {
                         ans = d;
                         x = tx;
                         y = ty;
                     }
                 }
             }
         }
     }
     printf("%.f\n",ans);
     return ;
 }