HDU 3367 Pseudoforest

题解：最大生成树加判环……

#include <cstdio>

#include <algorithm>

using namespace std;

struct node{int a,b,l;}seg[100005];

bool cmp(node a,node b){return a.l>b.l;}

int ans,m,n,f[10005],mark[10005];

int sf(int x){return f[x]==x?x:f[x]=sf(f[x]);}

int main(){

    while(scanf("%d%d",&n,&m)){

        if (m==0&&n==0)break; ans=0;

        for(int i=0;i<n;i++)f[i]=i,mark[i]=0;

        for(int i=0;i<m;i++)scanf("%d%d%d",&seg[i].a,&seg[i].b,&seg[i].l);

        sort(seg,seg+m,cmp);

        for(int i=0;i<m;i++){

            int q=sf(seg[i].a),w=sf(seg[i].b);

            if(q==w){

               if(mark[q]==0&&mark[w]==0) ans+=seg[i].l,mark[q]=1;

               continue;

            }else{

                if(mark[q]==1&&mark[w]==1)continue;

                if(mark[q]==1||mark[w]==1)ans+=seg[i].l,f[q]=w,mark[w]=1;

                else f[q]=w,ans+=seg[i].l;

            }

        } 

        printf("%d\n",ans);

    }

    return 0;

}