Brute force height queens solution - http://en.wikipedia.org/wiki/Eight_queens_puzzle

height_queens.rb

n = 8
cols = (0..n-1).to_a

def board(vec)
  vec.each do |col|
    s = '-' * vec.size
    s[col] = 'Q'
    puts s
  end
  puts ''
end

cols.permutation(cols.size).each do |vec|
  if (n == cols.map{|i| vec[i]+i}.uniq.size) && (n == cols.map{|i| vec[i]-i}.uniq.size)
    board vec
  end
end

heightqueens.py

from itertools import permutations

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

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)):
    board(vec)