PKU 1379 Run Away(模拟退火算法)

#include<ctime>
#include<cmath>
#include<cstdio>
#include<cstdlib>
const int shift=60;
const double inf=1e10;
const double pi=acos(-1.0);  
struct Point 
{
    double x,y;
}p[1010],randp[4];

double Get_Dis(Point a,Point b)
{
    return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
}
Point Get_Rand_Point(int a,int b)
{
    Point temp;
    temp.x=rand()%a+1;
    temp.y=rand()%b+1;
    return temp;
}
Point Goto_Rand_Dir(double key,Point temp)
{   
    double delta=2*pi*(double)rand()/RAND_MAX;
    temp.x+=key*sin(delta);
    temp.y+=key*cos(delta);
    return temp;
}

int main()
{
    double dis[5];
    int i,j,k,T,x,y,m;
    scanf("%d",&T);
    srand(time(NULL));
    while(T--){
        double now;
        Point temp;
        scanf("%d%d%d",&x,&y,&m);
        for(i=1;i<=m;i++)
            scanf("%lf%lf",&p[i].x,&p[i].y);
        for(i=1;i<=4;i++){//分别往四个方向找四个方向的最小值
            dis[i]=inf; 
            randp[i]=Get_Rand_Point(x,y);//给randp[]数组随机取横纵坐标值
            for(j=1;j<=m;j++){
                now=Get_Dis(randp[i],p[j]);
                if(now<dis[i]) dis[i]=now;//dis[i]存的是最小值 
            }
        } 
        double key=sqrt(1.0*(x*x+y*y))/2;//关键 
        while(key>=0.01){//精度要求 
            for(i=1;i<=4;i++){
                for(j=1;j<=shift;j++){
                    temp=randp[i];//采用之前四个方向确定的随机横纵坐标值 
                    temp=Goto_Rand_Dir(key,temp);
                    if(temp.x<0||temp.y<0||temp.x>x||temp.y>y) 
                        continue;
                    now=inf;
                    for(k=1;k<=m;k++){
                        double dist=Get_Dis(temp,p[k]);
                        if(now>dist) now=dist;//now存的是最小值 
                    }
                    if(now>dis[i]){
                        dis[i]=now;//dis[i]中存的是最小值最大 
                        randp[i]=temp;
                    }
                }
            }
            key=key*0.8;
        }
        for(i=1,k=1;i<=4;i++)//在四个方向中找最小值最大 
            if(dis[i]>dis[k]) k=i;
        printf("The safest point is (%.1lf, %.1lf).\n",randp[k].x,randp[k].y);
    }
}