poj 2420

来源：互联网发布：大数据双创中心是什么编辑：程序博客网时间：2024/05/01 10:45
#include <iostream>  #include <string.h>  #include <stdlib.h>  #include <stdio.h>  #include <time.h>  #include <math.h>    #define N 1005  #define eps 1e-8     //搜索停止条件阀值  #define INF 1e99       #define delta 0.98   //温度下降速度  #define T 100        //初始温度    using namespace std;    int dx[4] = {0, 0, -1, 1};  int dy[4] = {-1, 1, 0, 0};  //上下左右四个方向    struct Point  {      double x, y;  };    Point p[N];    double dist(Point A, Point B)  {      return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));  }    double GetSum(Point p[], int n, Point t)  {      double ans = 0;      while(n--)          ans += dist(p[n], t);      return ans;  }    //其实我觉得这玩意儿根本不叫模拟退火  double Search(Point p[], int n)  {      Point s = p[0];    //随机初始化一个点开始搜索      double t = T;      //初始化温度      double ans = INF;  //初始答案值      while(t > eps)      {          bool flag = 1;          while(flag)          {              flag = 0;              for(int i = 0; i < 4; i++)    //上下左右四个方向              {                  Point z;                  z.x = s.x + dx[i] * t;                  z.y = s.y + dy[i] * t;                  double tp = GetSum(p, n, z);                  if(ans > tp)                  {                      ans = tp;                      s = z;                      flag = 1;                  }              }          }          t *= delta;      }      return ans;  }    int main()  {      int n;      while(scanf("%d", &n) != EOF)      {          for(int i = 0; i < n; i++)              scanf("%lf %lf", &p[i].x, &p[i].y);          printf("%.0lf\n", Search(p, n));      }      return 0;  }
0 0