1 #include <iostream> 2 #include <string.h> 3 #include <stdio.h> 4 using namespace std; 5  6 const int maxn=27; 7  8 const int inf=0x7fffffff; 9 10 int village;11 12 int lowcost[maxn],adjvex[maxn];13 14 int G[maxn][maxn];15 16 int MinEdge()17 {18     int index = 0,temp=inf;19     for(int i=0; i<village; i++)20     {21         if(lowcost[i]!=-1&&lowcost[i]<temp)22         {23             temp=lowcost[i];24             index=i;25         }26     }27     //cout<<index<<endl;28     return index;29 }30 31 int prim()32 {33     int i,j,k;34     int sum=0;35     for (i = 1; i < village; i++)      //初始化两个辅助数组；36     {37         lowcost[i] = G[0][i];38         adjvex[i] = 0;39     }40     lowcost[0] = -1;             //将顶点0加入集合U中；41     for (i = 1; i < village; i++)42     {43         k = MinEdge();  //在lowcost中寻找最短边的顶点；44         sum += lowcost[k];45         lowcost[k] = -1;46         for (j = 1; j < village; j++)47             if (G[k][j]<lowcost[j]&&lowcost[j]!=-1)48             {49                 lowcost[j] = G[k][j];50                 adjvex[j] = k;51             }52     }53     return sum;54 }55 56 int main()57 {58     //freopen("in.txt","r",stdin);59     while(scanf("%d",&village)&&village!=0)60     {61         memset(G,127,sizeof(G));62         for(int j=1; j<village; j++)63         {64             char ch;65             int num;66             cin>>ch>>num;67             int start=ch-'A';68             for(int i=0; i<num; i++)69             {70                 char c;71                 int weight;72                 cin>>c>>weight;73                 int end = c-'A';74                 G[start][end]=weight;75                 G[end][start]=weight;76             }77         }78         int mincost=prim();79         printf("%d\n",mincost);80     }81     return 0;82 }