Find the special child ( child with maximum size )
int spcl_chld = -1 , spcl_edg_id ; for ( int j = 0 ; j < n ; j ++ ) if ( j != curr_node && j != node [ curr_node ] . par && tree [ curr_node ] [ j ] != -1 ) if ( spcl_chld == -1 node [ spcl_chld ] . size < node [ j ] . size ) spcl_chld = j , spcl_edg_id = tree [ curr_node ] [ j ] ;