To prove safety Offer 31

 1 # -*- coding:utf-8 -*-
 2 class Solution:
 3     def IsPopOrder(self, pushV, popV):
 4         n = len(pushV)
 5         stack = []
 6         popout = [0] * n
 7         preidx = 0
 8         for i in range(len(pushV)):
 9             cur = popV[i]
10             if pushV.count(cur) > 0:
11                 idx = pushV.index(cur)
12                 if idx >= preidx:
13                     for j in range(preidx,idx):
14                         if popout[j] == 1:
15                             continue
16                         else:
17                             stack.append(pushV[j])
18                 else:
19                     top = stack.pop(-1)
20                     if top != cur:
21                         return False
22                 popout[idx] = 1
23                 preidx = idx
24             else:
25                 return False
26         return True
27         # write code here