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我暂时只能看明白全排列的递归实现,效率已经比我那个愚蠢的方法快了两个数量级。
#!/usr/bin/python
import time
def display (x):
i = 0
while i8:
print x
i+=1
def display_method (method):
x = [[0 for i in range(8)] for j in range(8)]
for i in range(8):
x[method[0]][method[1]]=1
display(x)
def perm(s,k,m):
if k==m:
if(True==test(s[0],s[1],s[2],s[3],s[4],s[5],s[6],s[7])):
print s
else:
for i in range(m-k+1):
s[k],s[i+k]=s[i+k],s[k]
perm(s,k+1,m)
s[k],s[i+k]=s[i+k],s[k]
index = 1
def test(pos1 ,pos2 ,pos3,pos4,pos5,pos6,pos7,pos8) :
global index
method =([0,pos1],[1,pos2],[2,pos3],[3,pos4],[4,pos5],[5,pos6],[6,pos7],[7,pos8])
for i in range(8):
for j in range(i+1,8):
if attack(method,method[j])==True:
return False
print "**************************"
display_method(method)
print "This is " + str(index) + "method"
index+=1
return True
def attack(x,y):
if x[1] == y[1]:
return True
if ((x[0]-y[0])**2) == ((x[1]-y[1])**2):
return True
return False
x = [i for i in range(8)]
cur_time1=time.time()
print "Start time "+time.strftime( "%Y-%m-%d %X", time.localtime() )
perm(x,0,7)
cur_time2=time.time()
print "End time "+time.strftime( "%Y-%m-%d %X", time.localtime() )
print "Waste time "+str(cur_time2-cur_time1)+" seconds"
本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u2/72023/showart_1979214.html |
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