P3366 【模板】最小生成树

一道模板题，prim算法就可以过，krustal算法也是可以的嗷
这里只给出prim的结法

#include <bits/stdc++.h>
using namespace std;
const int N = 5010;
const int INF = 0x3f3f3f3f;
int n, m;
int g[N][N];
int dist[N];
bool st[N];
int prim()
{
    memset(dist, 0x3f, sizeof(dist));
    int res = 0;
    for (int i = 0; i < n; i++)
    {
        int t = -1;
        for (int j = 1; j <= n; j++)
        {
            if (!st[j] && (t == -1 || dist[t] > dist[j]))
                t = j;
        }
        if (i && dist[t] == INF) return INF;
        if(i) res+=dist[t];
        for(int j=1;j<=n;j++) dist[j]=min(dist[j],g[t][j]);
        st[t]=true;
    }
    return res;
}
int main()
{
    cin >> n >> m;
    memset(g, 0x3f, sizeof(g));
    for (int i = 0; i < m; i++)
    {
        int a, b, w;
        cin >> a >> b >> w;
        g[a][b] = g[b][a] = min(g[a][b], w);
    }
    int t = prim();
    if (t == INF) cout << "orz" << endl;
    else cout << t << endl;
    return 0;
}