#!/usr/bin/python
#queen_puzzle.py
import sys
def is_ok(queens):
m = [([0] * 8) for i in range(8)]
i = 0
for q in queens:
if m[i][q] == 0:
for j in range(8):
if m[i][j] == 1 or m[j][q] == 1:
return 0
else:
m[i][j] = 2
m[j][q] = 2
#######################################
if i > q:
j = i – q
k = 0
for l in range(8-j):
if m[j+l][k+l] == 1:
return 0
else:
m[j+l][k+l] = 2
else:
j = 0
k = q – i
for l in range(8-k):
if m[j+l][k+l] == 1:
return 0
else:
m[j+l][k+l] = 2
#######################################
n = i + q
if n < 8:
j = n
k = 0
for l in range(n+1):
if m[j-l][k+l] == 1:
return 0
else:
m[j-l][k+l] = 2
else:
j = 7
k = n -7
for l in range(8-k):
if m[j-l][k+l] == 1:
return 0
else:
m[j-l][k+l] = 2
#######################################
m[i][q] = 1
else:
return 0
i = i+1
return 1
def search_queens(queens):
if is_ok(queens):
if len(queens)==8:
return 1
else:
queens.append(0)
return 0
else:
while queens[len(queens)-1] == 7:
queens.pop()
queens[len(queens)-1] += 1
return 0
def queen_puzzle():
queens = []
steps = 0
while search_queens(queens)==0:
print queens
steps += 1
for i in range(8):
for j in range(8):
if queens[i] == j:
print ‘ *’,
else:
print ‘ -‘,
print ‘total steps=’,steps
if __name__ == ‘__main__’:
queen_puzzle()
