N-Queens

from itertools import permutations
 
n = 8
cols = range(n)
for vec in permutations(cols):
    if n == len(set(vec[i]+i for i in cols)) \
         == len(set(vec[i]-i for i in cols)):
        print ( vec )

def board(vec):
    '''Translate column positions to an equivalent chess board.

    >>> board([0, 4, 7, 5, 2, 6, 1, 3])
    Q-------
    ----Q---
    -------Q
    -----Q--
    --Q-----
    ------Q-
    -Q------
    ---Q----

    '''

    for col in vec:
        s = ['-'] * len(vec)
        s[col] = 'Q'
        print ''.join(s)
    print