0103-binary-tree-zigzag-level-order-traversal.adoc

103. Binary Tree Zigzag Level Order Traversal

{leetcode}/problems/binary-tree-zigzag-level-order-traversal/[LeetCode - Binary Tree Zigzag Level Order Traversal^]

思考题：思考一下如何使用深度优先来解决这个问题？

Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between).

For example:

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

    3
   / \
  9  20
    /  \
   15   7

return its zigzag level order traversal as:

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

思路分析

一刷

link:{sourcedir}/_0103_BinaryTreeZigzagLevelOrderTraversal.java[role=include]

二刷

link:{sourcedir}/_0103_BinaryTreeZigzagLevelOrderTraversal_2.java[role=include]

三刷

link:{sourcedir}/_0103_BinaryTreeZigzagLevelOrderTraversal_3.java[role=include]