POJ - 1287 Networking

https://vjudge.net/problem/POJ-1287

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
const int N=110,M=N*N/2;
int n,m;
int g[N][N],dis[N];
bool bk[N];
int prim()
{
	memset(dis,0x3f,sizeof dis);
	memset(bk,false,sizeof bk);
	int ans=0;
	for(int i=0;i<n;i++)
	{
		int t=-1;
		for(int j=1;j<=n;j++)
		{
			if(!bk[j] && (t==-1 || dis[t]>dis[j]))
				t=j;
		}
		bk[t]=true;
		if(i) ans+=dis[t];
		
		for(int j=1;j<=n;j++)
			if(dis[j]>g[t][j])
				dis[j]=g[t][j];
	}
	return ans;
}
int main()
{
	while(~scanf("%d",&n))
	{
		if(n==0) break;
		scanf("%d",&m);
		int a,b,c;
		memset(g,0x3f,sizeof g);
		for(int i=0;i<m;i++)
		{
			scanf("%d %d %d",&a,&b,&c);
			if(g[a][b]>c)
				g[a][b]=c;
			g[b][a]=g[a][b];
		}
		
		printf("%d\n",prim());
	}
	return 0;
}