gistfile1.txt

In [1]:         for q2 in range (1, len(board)-q1):
   ...:             if board[q1] == board[q1+q2] or board[q1+q2] == board[q1]+q2
   ...:  or board[q1+q2] == board[q1]-q2:
   ...:                 return False
   ...:     return True
   ...: 
   ...: def n_queens_solutions(n):
   ...:     board = []
   ...:     return n_queens_helper(0, board, n)
   ...: 
   ...: def n_queens_helper(n, board, size):
   ...:     if len(board) == size:
   ...:         print(board)
   ...:         yield board
   ...:     else:
   ...:         for i in range(size):
   ...:             board.append(i)
   ...:             if n_queens_valid(board):
   ...:                 yield from n_queens_helper(n+1, board, size)
   ...:             board.pop()
   ...: 
   ...: print(list(n_queens_solutions(4)))
   ...: 
   ...: 
[1, 3, 0, 2]
[2, 0, 3, 1]
[[], []]