八皇后问题的进化(4)-python写的八皇后

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　　这是“Beginning Python From Novice to Professional”里用python写的八皇后，代码量很少，用到了生成器。
　　python一直给我的感觉是：你可以全心全意用简洁的语言编程，而不用太关心语法问题,用C像是写报告，而用python更像是写诗。
　　


# 8 queens
def conflict(state,nextX):
nextY = len(state)
for i in range(nextY):
if abs(state-nextX) in (0,nextY - i ):
return True
return False
def queens(num=8,state=()):
for pos in range(num):
if not conflict(state,pos):
if len(state) == num - 1:
yield (pos,)
else:
for result in queens(num,state + (pos,)):
yield (pos,) + result
#show all solution
for solution in queens(8):
print solution
#count solution
print "The number of solutions is :"
print len(list(queens(8)))