104. Maximum Depth of Binary Tree.py

# -*- coding: utf-8 -*-
# @Time    : 2019/3/4 18:01
# @Author  : xulzee
# @Email   : xulzee@163.com
# @File    : 104. Maximum Depth of Binary Tree.py
# @Software: PyCharm

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

class Solution:
    def maxDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if root == None:
            return 0
        max_left = self.maxDepth(root.left)
        max_right = self.maxDepth(root.right)
        return max(max_left, max_right) + 1


def stringToTreeNode(input):
    input = input.strip()
    input = input[1:-1]
    if not input:
        return None

    inputValues = [s.strip() for s in input.split(',')]
    root = TreeNode(int(inputValues[0]))
    nodeQueue = [root]
    front = 0
    index = 1
    while index < len(inputValues):
        node = nodeQueue[front]
        front = front + 1

        item = inputValues[index]
        index = index + 1
        if item != "null":
            leftNumber = int(item)
            node.left = TreeNode(leftNumber)
            nodeQueue.append(node.left)

        if index >= len(inputValues):
            break

        item = inputValues[index]
        index = index + 1
        if item != "null":
            rightNumber = int(item)
            node.right = TreeNode(rightNumber)
            nodeQueue.append(node.right)
    return root


def main():
    import sys
    import io
    def readlines():
        for line in io.TextIOWrapper(sys.stdin.buffer, encoding='utf-8'):
            yield line.strip('\n')

    lines = readlines()
    while True:
        try:
            line = next(lines)
            root = stringToTreeNode(line);

            ret = Solution().maxDepth(root)

            out = str(ret);
            print(out)
        except StopIteration:
            break


if __name__ == '__main__':
    main()