102. Binary Tree Level Order Traversal刷题笔记

考察二叉树的层序遍历
问题描述
leetcode代码：

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def levelOrder(self, root: Optional[TreeNode]) -> List[List[int]]:
        result = []
        
        def recur(node,depth):
            if node:
                if depth==len(result):
                    result.append([])
                result[depth].append(node.val)
                recur(node.left,depth+1)
                recur(node.right,depth+1)
        recur(root,0)
        return result
        

运行结果：