problem0102

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102. Binary Tree Level Order Traversal

题目

Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).

For example: Given binary tree [3,9,20,null,null,15,7],

    3
   / \
  9  20
    /  \
   15   7

return its level order traversal as:

[
  [3],
  [9,20],
  [15,7]
]

解题思路

见程序注释

Documentation

Index

• type TreeNode

Types

type TreeNode

type TreeNode = kit.TreeNode