HDU 1233 prim (first blood)

http://acm.hdu.edu.cn/showproblem.php?pid=1233

#include<bits/stdc++.h>
using namespace std;
#define inf 0x3f3f3f3f
int n;
int mmp[101][101],dis[101],vis[101];
int prim()
{
    int i,j,pos,result=0;
    memset(vis,0,sizeof(vis));
    vis[1]=1;
    for(i=1; i<=n; i++)
        if(i!=1)
            dis[i]=mmp[1][i];
    for(i=1; i<n; i++)
    {
        int minn=inf;
        for(j=1; j<=n; j++)
        {
            if(!vis[j]&&minn>dis[j])
                minn=dis[pos=j];//注意别写反了
        }
        result+=minn;
        vis[pos]=1;
        for(j=1; j<=n; j++)
        {
            if(!vis[j]&&dis[j]>mmp[pos][j])
                dis[j]=mmp[pos][j];
        }
    }
    return result;
}
int main()
{

    while(scanf("%d",&n)!=EOF)
    {
        if(n==0)
            break;
        int m=n*(n-1)/2,i,j,a,b,c;
        for(i=1; i<=n; i++)
        {
            for(j=1; j<=n; j++)
                mmp[i][j]=inf;
        }
        for(i=1; i<=m; i++)
        {
            scanf("%d%d%d",&a,&b,&c);
            mmp[a][b]=c;
            mmp[b][a]=c;
        }
        int ans=prim();
        printf("%d\n",ans);
    }
    return 0;
}