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8Astar.py
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153 lines (146 loc) · 4.12 KB
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''' mbinary
#########################################################################
# File : 8Astar.py
# Author: mbinary
# Mail: [email protected]
# Blog: https://mbinary.xyz
# Github: https://github.com/mbinary
# Created Time: 2018-05-19 23:06
# Description:
#########################################################################
'''
isVisited = [0]*362880 # 0 for not visited,1 for occured,2 for visited
fac = [1,1,2,6,24,120,720,5040,40320]
lf = len(fac)
h = [[0,1,2,1,2,3,2,3,4],
[1,0,1,2,1,2,3,2,3],
[2,1,0,3,2,1,4,3,2],
[1,2,3,0,1,2,1,2,3],
[2,1,2,1,0,1,2,1,2],
[3,2,1,2,1,0,3,2,1],
[2,3,4,1,2,3,0,1,2],
[3,2,3,2,1,2,1,0,1],
[4,3,2,3,2,1,2,1,0]]
def cantor(s):
sum = 0
ls = len(s)
for i in range(ls):
count = 0
for j in range(i+1,ls):
if s[i] > s[j]: count +=1
sum += count*fac[lf-i-1]
return sum
que = []
dir = {-3:'u',1:'r',3:'d',-1:'l'}
class state:
flag = True
def __init__(self,s,x,f,step=0,last=0):
self.x = x
self.s = list(s)
self.step = step
self.path = []
self.last = last
self.f = f
def can(self):
cans = [-1,1,3,-3]
if self.last in cans :
cans.remove(-self.last)
if self.x<3:
cans.remove(-3)
if self.x>5:
cans.remove(3)
if self.x%3 is 0:
cans.remove(-1)
if self.x%3 is 2:
cans.remove(1)
return cans
def move(self):
cans = self.can()
for i in cans:
s = list(self.s)
tmp = self.x + i
s[self.x] = s[tmp]
s[tmp] = '9'
ct = cantor(s)
if isVisited[ct] != 2 :
val = int(s[self.x])
f = h[8][tmp] +h[val-1][self.x]-h[8][self.x]-h[val-1][tmp]+self.step+1
new = state(s,tmp,f,self.step +1,i)
new.path = self.path + [dir[i]]
if isVisited[ct] == 1:
for i,node in enumerate(que):
if mew.s == node.s:
del que[i]
break
else:isVisited[ct] = 1
if que == []:
que.append(new)
continue
for i,node in enumerate(que):
if new.f<=node.f:
que.insert(i,new)
def solvable(s):
reverse = 0
for i in range(8):
if s[i] is '9':continue
for j in range(i+1,9):
if s[i]>s[j]:reverse +=1
if reverse % 2 is 0:return True
else:return False
def getPath(s,index):
f = 0
for i,j in enumerate(s):
f+=h[int(j)-1][i]
que.append(state(s,index,f,0,0))
while que != []:
cur = que.pop(0)
ct = cantor(cur.s)
isVisited[ct] = 2
if ct is 0:
return cur.path
cur.move()
def info():
print('input a 3x3 matrix in one line')
print('from left to right,from up to down')
print('such as 56831247x represent matrix as follow')
print('5 6 8\n3 1 2\n4 7 x')
print('then, if it has, I will print the path of moving x to reach state as follows')
print('1 2 3\n4 5 6\n7 8 x')
print('print q to quit')
from random import shuffle
case = list('12345678x')
def genCase():
tmp = case.copy()
shuffle(tmp)
print(f'Using random data: {tmp}')
index = -1
for i,j in enumerate(tmp):
if j=='x':
index = i
break
tmp[index] = '9'
return tmp,index
def isValid(li):
for i in '123456789':
if not i in li:
print('Invalid Input')
return False
return True
def run():
while 1:
print('\n\n'+'-'*10+'Game Begins'+ '-'*10)
info()
s=input('input: ')
if s=='q' or s=='Q' or s=='quit':
break
index = s.find('x')
li = list(s)
if index != -1:
li[index] = '9'
if not isValid(li):
li, index = genCase()
if solvable(li):
print(''.join(getPath(li,index)))
else:print('unsolvable')
if __name__ == '__main__':
run()