Offer 31. 栈的压入、弹出序列

Offer 31. 栈的压入、弹出序列

1. python

class Solution:
    def validateStackSequences(self, pushed: List[int], popped: List[int]) -> bool:
        stack ,i = [],0
        for num in pushed:
            stack.append(num)
            while stack and stack[-1]==popped[i]: #此处是while  循环 ，必须家stack 非空 不然outoffange
                stack.pop()
                i+=1
        return not stack
  

  #1、首先pushed 入栈第一个元素，   如果 poped 【i】== stack 栈顶元素， 出栈 and i++

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