Binary-Tree-Zigzag-Level-Order-Traversal
Feb 11, 2018
第97天。 今天的题目是Binary Tree Zigzag Level Order Traversal: 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…