//poj2031 连接所有的球,让连接的线段和最小。
//记录所有两个球之间的线段。 最小生成树
#include <iostream>
#include <string>
#include <cmath>
#include <iomanip>
using namespace std;
double inf = 10000;
double x[105], y[105], z[105], r[105];
double weight[105][105];
double dist[105];
bool mark[105];
double sum;
double compute(int m, int n)
{
double xx = (x[m] - x[n]) * (x[m] - x[n]);
double yy = (y[m] - y[n]) * (y[m] - y[n]);
double zz = (z[m] - z[n]) * (z[m] - z[n]);
double dis = 0;
dis += sqrt(xx + yy + zz);
dis -= (r[m] + r[n]);
return dis;
}
double prime(int n)
{
dist[0] = 0;
mark[0] = true;
//初始化距离表
for(int i = 1; i < n; i++)
{
dist[i] = weight[0][i];
}
for(int i = 1; i < n; i++)
{
//寻找距离党组织最近的点
double min1 = inf;
int minIndex = -1;
for(int j = 1; j < n; j++)
{
if(!mark[j] && dist[j] < min1)
{
min1 = dist[j];
minIndex = j;
}
}
//加入党组织,更新距离表
sum += dist[minIndex];
dist[minIndex] = 0;
mark[minIndex] = true;
for(int j = 1; j < n; j++)
{
if(!mark[j])
dist[j] = (weight[minIndex][j] < dist[j])?weight[minIndex][j]:dist[j];
}
}
return sum;
}
int main()
{
int n;
cin>>n;
while(n)
{
sum = 0;
for(int i = 0; i < n; i++)
{
dist[i] = inf;
for(int j = 0; j < n; j++)
{
weight[i][j] = inf;
weight[j][i] = inf;
}
}
memset(mark, 0, sizeof(mark));
for(int i = 0; i < n; i++)
weight[i][i] = 0;
for(int i = 0; i < n; i++)
{
cin>>x[i]>>y[i]>>z[i]>>r[i];
if(i != 0)
{
for(int j = 0; j < i; j++)
{
double temp = compute(j, i);
if(temp < 0)
weight[j][i] = 0;
else
weight[j][i] = temp;
weight[i][j] = weight[j][i];
}
}
}
cout<<fixed<<setprecision(3)<<prime(n)<<endl;
cin>>n;
}
return 0;
}
poj2031 连接所有的球,让连接的线段和最小。
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转载自blog.csdn.net/chchlh/article/details/43761533
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