POJ2069 最小球体覆盖, 模拟退火

只是套了个模板，模拟退火具体的过程真心不懂阿

//#pragma comment(linker, "/STACK:16777216") //for c++ Compiler
#include <stdio.h>
#include <iostream>
#include <cstring>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <algorithm>
#define ll long long
#define Max(a,b) (((a) > (b)) ? (a) : (b))
#define Min(a,b) (((a) < (b)) ? (a) : (b))
#define Abs(x) (((x) > 0) ? (x) : (-(x)))
using namespace std;

const int INF = 0x3f3f3f3f;
const int MAXN = 220;
const double eps = 1e-8;
int n;
struct POINT{
    double x,y,z;
}ps[35],q;

double dist(POINT a,POINT b){
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y)+(a.z-b.z)*(a.z-b.z));
}

int maxD(POINT p){
    double res = 0;
    int i, k = 0;
    for(i = 0; i < n ; ++i){
        double tmp = dist(p,ps[i]);
        if(tmp > res){
            k = i;
            res = dist(p,ps[i]);
        }
    }
    return k;
}

double BallCover(){
    double step = 100, ans = INF;
    q.x = q.y = q.z = 0.0;
    while(step > eps){
        int d = maxD(q);
        double tmp = dist(ps[d],q);
        if(tmp < ans) ans=tmp;
        double dx = ps[d].x - q.x;
        double dy = ps[d].y - q.y;
        double dz = ps[d].z - q.z;
        dx /= tmp;
        dy /= tmp;
        dz /= tmp;
        q.x += (dx*step);
        q.y += (dy*step);
        q.z += (dz*step);
        step *= 0.98;
    }
    return ans;
}

int main(){
    int i;
    while(EOF != scanf("%d",&n)){
        if(0 == n)  break;
        for(i = 0; i < n ; ++i)
            scanf("%lf%lf%lf",&ps[i].x,&ps[i].y,&ps[i].z);
        printf("%.5f
",BallCover());
    }
    return 0;
}