Poj(1251),Prim字符的最小生成树

#include <stdio.h>
#include <string.h>

#define INF 0x3f3f3f3f

int maps[305][305];
bool vis[305];
int dis[305];
int n;

int Prim()
{
    memset(vis,false,sizeof(vis));
    for(int i=1; i<=n; i++)
        dis[i] = INF;
    int ans=0;
    dis[1] = 0;
    for(int i=1; i<=n; i++)
    {
        int tmp = INF,k=0;
        for(int j=1; j<=n; j++)
        {
            if(!vis[j]&&dis[j]<tmp)
            {
                tmp = dis[j];
                k=j;
            }
        }

        vis[k] = true;
        ans+=tmp;
        for(int i=1; i<=n; i++)
        {
            if(!vis[i]&&dis[i]>maps[k][i])
                dis[i] = maps[k][i];
        }
    }
    return ans;
}

int main()
{
    while(scanf("%d",&n),n)
    {
        for(int i=0; i<=n; i++)
        {
            for(int j=0; j<=n; j++)
                if(i==j)
                    maps[i][j]=0;
                else maps[i][j] = INF;
        }
        for(int i=0; i<n-1; i++)
        {
            int t;
            char a[2],b[2];
            scanf("%s%d",a,&t);
            for(int j=0; j<t; j++)
            {
                int dist;
                scanf("%s%d",b,&dist);
                maps[a[0]-‘A‘+1][b[0]-‘A‘+1] = maps[b[0]-‘A‘+1][a[0]-‘A‘+1] = dist;
            }
        }
        printf("%d\n",Prim());
    }
    return 0;
}