poj1379模拟退火

　　题意： 求一个点到给出点最短距离最长的那个点。

     看rp  迭代次数越多和 初始随机点越多 应该越准确（初始随机点坑了，多了也不一定准确）。

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <climits>
#include <string>
#include <iostream>
#include <map>
#include <cstdlib>
#include <list>
#include <set>
#include <queue>
#include <stack>
#include<time.h>
#define eps 1e-4
using namespace std;
const double maxn = 1e30;
const int dx[] = { 0, 0, 1, -1, 1, -1, 1, -1 };
const int dy[] = { 1, -1, 0, 0, -1, 1, 1, -1 };
int bx[2000], by[2000];
int X, Y;
int gx[105], gy[105];
int m;
double gao(double x, double y, double x1, double y1)
{
    return sqrt((x - x1)*(x - x1) + (y - y1) *(y - y1));
}

int gao1(double x, double y)
{
    if (x >= 0 && x <= X&&y >= 0 && y <= Y) return 1;
    return 0;
}
double dis(double x, double y)
{
    double sum = maxn;
    for (int i = 0; i < m; i++){
        sum = min(sum, gao(x, y, bx[i], by[i]));
    }
    return sum;
}

void gaomaoxian()
{
    double x, y;
    double Rand = max(X, Y);
    double Max = 0;
    for (int i = 0; i < 100; i++){
        double dist = dis(gx[i], gy[i]);
        if (dist>Max) Max = dist, x = gx[i], y = gy[i];
    }
    while (Rand>eps){
        double xx = x; double yy = y;
        for (int i = 0; i < 8; i++){
            double x1 = xx + dx[i] * Rand; double y1 = yy + dy[i] * Rand;
            if (!gao1(x1, y1))continue;
            double dist = dis(x1, y1);
            if (dist > Max) Max = dist, x = x1, y = y1;
        }
        Rand *= 0.99;
    }
    printf("The safest point is (%.1f, %.1f).
", x, y);
}

int main()
{
    int Icase;
    cin >> Icase;
    while (Icase--){
        cin >> X >> Y >> m;
        srand(clock());
        for (int i = 0; i < m; i++)
            cin >> bx[i] >> by[i];
        for (int i = 0; i < 100; i++){
            gx[i] = rand() % X; gy[i] = rand() % Y;
        }
        gaomaoxian();
    }
    return 0;
}