POJ:1287 Networking

题意：给你一些地点以及之间的长度，问你连接所有地点的最小长度。

思路：纯裸最小生成树。

 

#include <iostream>
#include <cstdio>
#include <queue>
#include <cstring>
#include <algorithm>
#define MAXN 100005
using namespace std;
struct Edge
{
    int a,b,weight;
};
bool cmp(Edge x,Edge y)
{
    return x.weight<y.weight;
}
int father[MAXN];
int find(int p)
{
    return p==father[p]?p:(father[p]=find(father[p]));
}
int main()
{
    int n,m;
    while(scanf("%d",&n)&&n)
    {

        scanf("%d",&m);
        Edge p[MAXN];
        for(int i=0; i<m; ++i)
            scanf("%d%d%d",&p[i].a,&p[i].b,&p[i].weight);
        sort(p,p+m,cmp);
        for(int i=0; i<=n; ++i)
            father[i]=i;
        int ans=0;
        for(int i=0; i<m; ++i)
        {
            int ta=find(p[i].a),tb=find(p[i].b);
            if(ta!=tb)
            {
                father[ta]=tb;
                ans+=p[i].weight;
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}