Expert System Lab 6

es6.py

import operator

chars = {True: 'QQ|', False: '__|'}

def queens(x, y):
  def go_deep(xs, ys, us, vs):
    if len(xs) == 0:
      return ()

    row = xs[0]
    for col in ys:
      u = row - col
      v = row + col
      if u in us and v in vs:
        col_i = ys.index(col)
        u_i = us.index(u)
        v_i = vs.index(v)
        queens = go_deep(xs[1:], ys[:col_i] + ys[col_i + 1:],\
          us[:u_i] + us[u_i + 1:], vs[:v_i] + vs[v_i + 1:])
        if queens is not None:
          print_queens(queens)
          print ""
          return ((row, col),) + queens
    return None

  xs = range(8)
  ys = range(8)
  us = range(-7, 8)
  vs = range(15)
  us.remove(x - y)
  vs.remove(x + y)
  return ((x, y),) + go_deep(xs[:x] + xs[x + 1:], ys[:y] + ys[y + 1:], us, vs)

def print_queens(queens):
  for i in range(8):
    print '|' + reduce(operator.__add__, map(lambda p: chars[p in queens],\
      zip((i,) * 8, range(8))), "")

print "Queens"
x = int(raw_input("x>>>"))
y = int(raw_input("y>>>"))

if x not in range(8) or y not in range(8):
  print "Coordinates must be in range [0:7]"
else:
  print_queens(queens(x, y))
raw_input()