sicily 1083 Network【最小生成树】

最小生成树的水题，直接上代码了。

// source code of submission 689439, Zhongshan University Online Judge System
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
struct Edge
{
    int u,v,length;
    Edge(int uu,int vv,int ll): u(uu),v(vv),length(ll) {}
};
vector<Edge> vec;
int root[60];
int P,R;

bool cmp(Edge x,Edge y)
{
    return (x.length < y.length);
}

void makeSet()
{
    for(int i = 0;i <= 60;++i) root[i] = -1;
}

int findSet(int x)
{
    while(root[x] >= 0) x = root[x];
    
    return x;
}

void unionSet(int a,int b)
{
    int x = findSet(a),y = findSet(b);

    root[x] = y;
}


int main()
{
    int u,v,l,i;
    while(true)
    {
        cin>>P; 
        if(P == 0) break;
        cin>>R;

        for(i = 0;i < R;++i)
        {
            cin>>u>>v>>l;
            vec.push_back(Edge(u,v,l));
        }

        sort(vec.begin(),vec.end(),cmp);
        int ans = 0;    makeSet();

        for(i = 0;i < vec.size();++i)
        {
            int x = findSet(vec[i].u),y = findSet(vec[i].v);

            if(x != y)
            {
                ans += vec[i].length;
                unionSet(x,y);
            }
        }
        cout<<ans<<endl;
        vec.clear();
    }

    return 0;
}