1 #include <iostream> 2 #include <cstring> 3 using namespace std; 4  5 const int size = 1010; 6 int father[size]; 7  8 int find( int x ) 9 {10     return father[x] == -1 ? x : father[x] = find( father[x] );11 }12 13 void Union( int x , int y )14 {15     x = find(x);16     y = find(y);17     if( x!=y )18     {19         father[x] = y;20     }21 }22 23 int main()24 {25     int t , n , m , cnt , x , y;26     cin >> t;27     while( t-- )28     {29         cnt = 0;30         cin >> n >> m;31         memset( father , -1 , sizeof(father) );32         while( m-- )33         {34             cin >> x >> y;35             Union( x, y );36         }37         for( int i = 1 ; i<=n ; i++ )38         {39             if( father[i] == -1 )40             {41                 cnt ++;42             }43         }44         cout << cnt << endl;45     }46     return 0;47 }