HDU 1879 继续畅通工程(最小生成树 Kruskal算法)

#include<iostream>#include<cstring>#include<algorithm>using namespace std;#define M 101typedef struct egde{int e,s,weight;bool build;}egde;egde info[M*M/2];int c[M],n,num;bool cmp(const egde a,const egde b){if(a.build!=b.build)return a.build<b.build;return a.weight<b.weight;}int Find(int x){while(x!=c[x])x=c[x];return x;}bool Union(int x,int y){int a=Find(x),b=Find(y);if(a==b)return false;num++;c[a]=b;return true;}void init(){int b;num=0;for(int i=1;i<=n*(n-1)/2;i++){scanf("%d %d %d %d",&info[i].e,&info[i].s,&info[i].weight,&b);info[i].build=b?false:true;i<=n?c[i]=i:1;}sort(info+1,info+n*(n-1)/2+1,cmp);}int MST_Kruskal(){int mincost=0;for(int i=1;i<=n*(n-1)/2 && num<n-1 ;i++){if(Union(info[i].s,info[i].e))mincost+=info[i].weight*info[i].build;}return mincost;}int main(){while(cin>>n && n){init();cout<<MST_Kruskal()<<endl;}return 0;}