### 模擬退火法模板

```#include"string.h"
#include"stdio.h"
#include"iostream"
#include"queue"
#include"stack"
#define M 10009
#define N 100009
#include"stdlib.h"
#include"math.h"
#define inf 99999999
#define eps 1e-8
#define PI acos(-1.0)
using namespace std;
struct node
{
double x,y,dis;
}p[6],q[100];
double max(double x,double y)
{
return x>y?x:y;
}
double min(double x,double y)
{
return x<y?x:y;
}
double len(node a,node b)
{
return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
double fun(node q)
{
double sum=0;
for(int i=0;i<4;i++)
sum+=len(q,p[i]);
return sum;
}
int main()
{
int i,j;
while(scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&p[0].x,&p[0].y,&p[1].x,&p[1].y,&p[2].x,&p[2].y,&p[3].x,&p[3].y)!=-1)
{
int flag=0;
for(i=0;i<4;i++)
if(fabs(p[i].x+1)<eps&&fabs(p[i].y+1)<eps)
flag++;
if(flag==4)
break;
node a,b;
a.x=a.y=inf;
b.x=b.y=-inf;
for(i=0;i<4;i++)
{
a.x=min(a.x,p[i].x);
a.y=min(a.y,p[i].y);
b.x=max(b.x,p[i].x);
b.y=max(b.y,p[i].y);
}
for(i=1;i<=20;i++)//枚舉的時候盡量在內部枚舉這些點
{
q[i].x=(rand()%1000+10)/1000.0*(b.x-a.x)+a.x;//
q[i].y=(rand()%1000+10)/1000.0*(b.y-a.y)+a.y;//
q[i].dis=fun(q[i]);
}
double temp=len(a,b);
while(temp>eps)
{
for(i=1;i<=20;i++)
{
for(j=0;j<25;j++)
{
node cur;
if(cur.x<a.x||cur.y<a.y||cur.x>b.x||cur.x>b.y)continue;
cur.dis=fun(cur);
if(cur.dis<q[i].dis)
q[i]=cur;
}
}
temp*=0.981;
}
double mini=q[1].dis;
for(i=2;i<=20;i++)
{
if(mini>q[i].dis)
mini=q[i].dis;
}
printf("%.4lf\n",mini);
}
}
```