题解 | #求二叉树的层序遍历#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @return int整型二维数组
#
class Solution:
    def levelOrder(self , root: TreeNode) -> List[List[int]]:
        # write code here
        if root is None:
            return []
        que = [[root,0]]
        res = [[]]
        while len(que)>0:
            this,depth = que.pop(0)
            if depth+1>len(res):
                res.append([])
                res[depth].append(this.val)
            else:
                res[depth].append(this.val)
            if this.left is not None:
                que.append([this.left,depth+1])
            if this.right is not None:
                que.append([this.right,depth+1])
        
        return res