Verify Preorder Serialization of a Binary Tree.py

class Solution:
    def isValidSerialization(self, preorder: str) -> bool:
        
        #print(preorder)
        
        # 一個element一個element加  
        ## 過程中 遇到 (number # #) => #
        ## 如果都沒有 (number # #)，則繼續一個 element 一個 element 加
        
        stack_list=preorder.split(",")
        print(stack_list)
        stack_list.reverse()
        
        another_stack = []
        cnt=0
        while len(stack_list)!=0:
            tmp=stack_list.pop()
            another_stack.append(tmp)
            
            while len(another_stack)>=3:
                rc=another_stack[-3:]
                #print(rc[0],rc[1],rc[2])
                if rc[0]!="#" and rc[1]=="#" and rc[2]=="#":
                    another_stack.pop(),another_stack.pop(),another_stack.pop()
                    another_stack.append("#")
                else:
                    break
        print(another_stack)            
        if len(another_stack)==1 and another_stack[0]=="#":
            return True
        return False