【栈、树、字符串、二叉树-中等】331. 验证二叉树的前序序列化

【题目】
【代码】

class Solution:
    def isValidSerialization(self, preorder: str) -> bool:
        queue=[]
        c=preorder.split(",")
        if len(c)%2==0 or (preorder[0]=="#" and len(preorder)>1):
            return False
        cnt=0
        while c:
            temp=c.pop(0)
            queue.append(temp)
            if  len(queue)>=3 and queue[-1]==queue[-2] and queue[-1]=="#":
                while len(queue)>=3 and queue[-1]==queue[-2] and queue[-1]=="#":
                    queue.pop(-1)
                    queue.pop(-1)
                    queue.pop(-1)
                    if queue:
                        queue.append("#")
        return queue==[] or queue==['#']
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