poj2031 Building a space station the smallest spanning tree in three dimensions

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Test instructions

In three-dimensional space, there are n spherical space stations, which give the three-dimensional coordinates x, Y, z and radius of each space station. There may be intersections, inclusions, and other conditions between space stations. If not, the distance between the two space stations is 0. Minimum spanning tree for all space stations.

Exercises

Three-dimensional composition the distance between the two space stations equals two circle distance minus the radius of two circles if the distance is less than 0, the distance is 0

In the set Kruskal template can be

Code:

#include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <    cmath>using namespace std;struct node{int u,v; Double W;} EDGE[10005];d ouble map[105][4],ans;int fa[105];int m,s;int cmp (node A,node b) {return A.W&LT;B.W;}    int find (int x) {int d=x,t;    while (fa[d]>=0) d=fa[d];        while (X!=d)//compression path {t=fa[x];        Fa[x]=d;    x=t; } return D;}    void Kruskal () {int r1,i,j,r2,n=0,ss;        for (i=0; i<s; i++) {r1=find (edge[i].u), R2=find (EDGE[I].V);            if (R1!=R2) {n++;            SS=FA[R1]+FA[R2];            ANS+=EDGE[I].W;            if (FA[R1]&LT;FA[R2]) fa[r1]=ss,fa[r2]=r1;        else Fa[r1]=r2,fa[r2]=ss;    } if (n==m-1) break; } return;    int main () {int i,j;    Double weight;        while (scanf ("%d", &m) &&m) {ans=s=0;        memset (fa,-1,sizeof (FA)); for (I=1; i<=m; i++) {scanf ("%lf%lf%lf%lf", &map[i][0],&map[i][1],&map[i][2],&map[i][3]);                for (j=1; j<i; J + +) {edge[s].u=j,edge[s].v=i;                Weight=sqrt (Pow (map[i][0]-map[j][0],2) +pow (map[i][1]-map[j][1],2) +pow (map[i][2]-map[j][2],2));                if (weight>map[i][3]+map[j][3])//distance edge[s++].w=weight-map[i][3]-map[j][3];            else edge[s++].w=0;        }} sort (edge,edge+s,cmp);        Kruskal ();    printf ("%.3lf\n", ans); } return 0;}

poj2031 Building a space station the smallest spanning tree in three dimensions