题解 | #栈的压入、弹出序列#

# -*- coding:utf-8 -*-
class Solution:
    def IsPopOrder(self, pushV, popV):
        # write code here
        # result = True
        l = []
        j = 0 # 用于标识弹出序列的位置
        for i in range(len(pushV)): # 思路：遍历pushV的元素压入l,每次压入后进行判断l栈顶是否与popV当前位置元素相同
            l.append(pushV[i])
            # while 条件，判断辅助栈的栈顶元素是否等于popV[j] 
            while l and l[-1] == popV[j]:
                # 符合条件则辅助栈弹出栈顶元素
                l.pop()
                j += 1
        return l == [] # 根据l是否为空判断输出结果
'''        while j < len(pushV):
            if l and l[-1] == popV[j]:
                l.pop()
                j += 1
            else:
                l.append(pushV[i])
                i += 1
        if l == []:
            return True
        else:
            return False'''
            
'''            l.append(pushV.pop())
        for i in range(len(l)):
            if l[i] != popV:
                result = False
        return result'''