HDU1213直接并查集

HDU1213直接并查集

http://acm.hdu.edu.cn/showproblem.php?pid=1213

刚睡觉起来，一不注意把parent初始化为0了，惭愧呀。。。

#include  < iostream >

using   namespace  std;

const   int  M = 1001 ;
int  parent[M];
int  uffind( int  i)
{
     int  j,temp;
     for (j = i;parent[i] >= 0 ;i = parent[i]);
     while (j != i)
    {
        temp = parent[j];
        parent[j] = i;
        j = temp;
    }
     return  i;
}

void  ufunion( int  i, int  j)
{
     int  temp;
    i = uffind(i);
    j = uffind(j);
     if (i == j)
         return ;
    temp = parent[i] + parent[j];
     if (parent[i] <= parent[j])
    {
        parent[i] = temp;
        parent[j] = i;
    }
     else
    {
        parent[j] = temp;
        parent[i] = j;
    }
}

int  main()
{
     int  t,m,n,i,j,res;
    cin >> t;
     while (t -- )
    {
        memset(parent, - 1 , sizeof (parent));
        res = 0 ;
        cin >> n >> m;
         while (m -- )
        {
            cin >> i >> j;
            ufunion(i,j);
        }
         for (i = 1 ;i <= n;i ++ )
             if (parent[i] < 0 )
                res ++ ;
        cout << res << endl;
    }
     return   0 ;
}