L - 还是畅通工程

L - 还是畅通工程

 

思路：水！

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 10010
using namespace std;
int fa[];
int n,m,ans,tot;
struct nond{
    int x,y,z;
}v[MAXN];
int cmp(nond a,nond b){
    return a.z<b.z;
}
int find(int x){
    if(fa[x]==x)    return x;
    else return fa[x]=find(fa[x]);
}
int main(){
    while(scanf("%d",&n)&&n){
        m=n*(n-)/;
        for(int i=;i<=m;i++)
            scanf("%d%d%d",&v[i].x,&v[i].y,&v[i].z);
        sort(v+,v++m,cmp);
        for(int i=;i<=n;i++)    fa[i]=i;
        for(int i=;i<=m;i++){
            int dx=find(v[i].x);
            int dy=find(v[i].y);
            if(dx==dy)    continue;
            fa[dy]=dx;tot++;
            ans+=v[i].z;
            if(tot==n-)    break;
        }
        printf("%d\n",ans);ans=;tot=;
    }
}