331-Verify-Preorder-Serialization-Of-A-Binary-Tree

Sat 17 May 2025

https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree

import pyutil as pyu
pyu.get_local_pyinfo()

print(pyu.ps2("python-dotenv"))

from typing import List

class Solution:
  def isValidSerialization(self, preorder: str) -> bool:
    degree = 1  # OutDegree (children) - inDegree (parent)

    for node in preorder.split(','):
      degree -= 1
      if degree < 0:
        return False
      if node != '#':
        degree += 2

    return degree == 0

new Solution().isValidSerialization()

Score: 5

Category: leetcode