84求调

#include<bits/stdc++.h>
using namespace std;
const int N=5001;
const int INF=0x3f3f3f3f3f3f;
bool vis[N];
int n,m,dis[N],g[N][N];
int prim(int s){
	int sum=0,cnt=0;
	memset(vis,0,sizeof(vis));
	memset(dis,0x3f,sizeof(dis));
	dis[s]=0;
	for(int i=1;i<=n;i++){
		int u,minn=INF;
		for(int j=1;j<=n;j++){
			if(!vis[j]&&minn>dis[j]){
				minn=dis[j];
				u=j;
			}
		}
		cnt++;
		vis[u]=1;
		sum+=minn;
		for(int v=1;v<=n;v++){
			if(!vis[v]&&dis[v]>g[u][v]){
				dis[v]=g[u][v];
			}
		}
	}
	if(cnt<n)sum=-1;
	return sum;
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			g[i][j]=INF;
			if(i==j)g[i][j]=0;
		}
	}
	int u,v,w;
	for(int i=1;i<=m;i++){
		cin>>u>>v>>w;
		if(g[u][v]>w){
			g[u][v]=w;
			g[v][u]=w;
		}
	}
	int ans=prim(1);
	if(ans==-1)cout<<"orz\n";
	else cout<<ans<<"\n";
}