HDU1102MST

HDU1102MST

http://acm.hdu.edu.cn/showproblem.php?pid=1102

#include  < iostream >
#include  < cmath >

using   namespace  std;


const   int  M = 27 ;
const   int  MAX = 10000000 ;


int  map[M][M];
int  dis[M];  // 存储i节点到当前节点的最短距离
bool  visit[M];
int  n;
int  res;  // 结果

int  min( int  a, int  b)
{
     return  a < b ? a:b;
}

void  prim( int  v)
{
     int  i,j,t;
     int  min;
     for (i = 1 ;i <= n;i ++ )
    {
        dis[i] = map[v][i];
        visit[i] = false ;
    }
    visit[v] = true ;
    res = 0 ;
     for (t = 1 ;t < n;t ++ )  // 找点
    {
        min = MAX;
         for (i = 1 ;i <= n;i ++ )
             if (dis[i] < min  &&   ! visit[i])  // 找到未访问过的到当前节点最短的点
            {
                min = dis[i];
                j = i;
            }
         if (min == MAX)
             break ;
        res += min;
        visit[j] = true ;
         for (i = 1 ;i <= n;i ++ )             // 更新dis数组
             if (map[j][i] < dis[i])
                dis[i] = map[j][i];
    }
}

int  main()
{
     int  i,j,k,d,t;
     char  ch,c;
     while (scanf( " %d " , & n) != EOF,n)
    {
         for (i = 1 ;i <= n;i ++ )
             for (j = 1 ;j <= n;j ++ )
                 if (i == j)
                    map[i][j] = 0 ;
                 else
                    map[i][j] = MAX;
         for (t = 1 ;t < n;t ++ )
        {
            scanf( " %c%c " , & c, & ch);
             // cin>>ch;
            i = ch - ' A ' + 1 ;
            scanf( " %d " , & k);
             while (k -- )
            {
                scanf( " %c%c " , & c, & ch);
                 // cin>>ch;
                j = ch - ' A ' + 1 ;
                scanf( " %d " , & d);
                map[i][j] = map[j][i] = d;
            }
        }
        prim( 1 );
        printf( " %d\n " ,res);
    }
     return   0 ;
}