最小生成树

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>
#include <cstring>
#include <cstdlib>
#include <map>
#include <vector>
#include <set>
#include <queue>
#include <stack>
#include <cmath>
using namespace std;
#define mem(s,t) memset(s,t,sizeof(s))
#define pq priority_queue
#define pb push_back
#define fi first
#define se second
#define ac return 0;
#define TLE std::ios::sync_with_stdio(false);   cin.tie(NULL);   cout.tie(NULL);   cout.precision(10);
const int mxn = 1e3;
int root[mxn];
int n,m,k,l,r,t,ans,cnt;
struct node
{
    int x,y,k;
    bool operator <(const node &a) const
    {
        return k<a.k;
    }
}no[50+5];
void init() {for(int i=0;i<=mxn;i++) root[i]=i;}
int Judge(int now)
{
    if( now==root[now] )
        return now;
    root[now] = Judge(root[now]);
    return root[now];
}
int check(int x,int y)
{
    if(Judge(x)==Judge(y))
        return 0;
    root[Judge(x)]=Judge(y);
    return 1;
}
int main()
{
    TLE;
    while(cin>>n&&n)
    {
        cin>>m;
        init(); ans = 0,cnt = 0 ;
        for(int i=1;i<=m;i++)
            cin>>no[i].x>>no[i].y>>no[i].k;
        sort(no+1,no+1+m);
        for(int i=1;i<=m;i++)
        {
            if( check( no[i].x,no[i].y ) )
            {
                cnt++;
                ans += no[i].k;
            }
            if(cnt==n-1) break;
        }
        cout<<ans<<endl;
    }
    return 0;
}