Uva 10397 - Connect the Campus

1Y

并查集+最小生成树

#include<stdio.h>#include<vector>#include<algorithm>#include<math.h>#define MAX 800struct edge{int p,q;double w;bool operator < (const edge& b)const {return w<b.w;}};std::vector<edge>L;int ft[MAX];void in_ft(int n){int i;for(i=1;i<=n;i++)ft[i]=i;}int find(int x){int t=x,temp;while(ft[x]!=x)x=ft[x];while(t!=x){temp=ft[t];ft[t]=x;t=temp;}return x;}void merge(int root1,int root2){int fr1=find(root1);int fr2=find(root2);ft[fr1]=fr2;}double x[MAX],y[MAX];double dis(int p,int q){double xx=x[p]-x[q];double yy=y[p]-y[q];return sqrt(xx*xx+yy*yy);}int main(){int z=0,n;while(scanf("%d",&n)!=EOF&&n){L.clear();in_ft(n);int i,j;for(i=1;i<=n;i++){scanf("%lf%lf",&x[i],&y[i]);for(j=1;j<i;j++){L.push_back( (edge){j,i,dis(i,j)} );}}        int m;        scanf("%d",&m);        double res=0;        for(i=1;i<=m;i++){            int p,q;            scanf("%d%d",&p,&q);            merge(p,q);       //     res+=dis(p,q);            }std::sort(L.begin(),L.end());//printf("Scenario #%d\n",++z);for(i=0;i<L.size();i++){if( find(L[i].p) != find(L[i].q) ){merge(L[i].p,L[i].q);res+=L[i].w;}}printf("%.2lf\n",res);}return 0;}