47-1.py

import collections


# Definition for a binary tree node.
class TreeNode:
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None


class Codec:
    # 직렬화
    def serialize(self, root: TreeNode) -> str:
        queue = collections.deque([root])
        result = ['#']
        # 트리 BFS 직렬화
        while queue:
            node = queue.popleft()
            if node:
                queue.append(node.left)
                queue.append(node.right)

                result.append(str(node.val))
            else:
                result.append('#')
        return ' '.join(result)

    # 역직렬화
    def deserialize(self, data: str) -> TreeNode:
        # 예외 처리
        if data == '# #':
            return None

        nodes = data.split()

        root = TreeNode(int(nodes[1]))
        queue = collections.deque([root])
        index = 2
        # 빠른 런너처럼 자식 노드 결과 먼저 확인 후 큐 삽입
        while queue:
            node = queue.popleft()
            if nodes[index] is not '#':
                node.left = TreeNode(int(nodes[index]))
                queue.append(node.left)
            index += 1

            if nodes[index] is not '#':
                node.right = TreeNode(int(nodes[index]))
                queue.append(node.right)
            index += 1
        return root