Board size
int n = 4 ; int ways = 0 ; vector < vector < char > > board ; for ( int i = 0 ; i < n ; i ++ ) { vector < char > tmp ; for ( int j = 0 ; j < n ; j ++ ) { tmp . push_back ( ' ▁ ' ) ; } board . push_back ( tmp ) ; } int rowmask = 0 , ldmask = 0 , rdmask = 0 ; int row = 0 ;