英语的学习
acquisition
n. 收购 并购 购买 添置
If a company or business person makes an acquisition, they buy another company or part of a company.
前缀：ac- = to 去、往
词根：quis = seek, ask 寻求，问
后缀：ition = 名词, 表：行为、过程
ankle
n. 脚踝
Your ankle is the joint where your foot joins your leg.
前缀：ank = to bend 弯、钩
后缀：-le = 名词, 表示：小~
carbohydrate
n. 碳水化合物
Carbohydrates are substances, found in certain kinds of food, that provide you with energy...
词根：carbo = carbon 碳
词根：hydr = water 水
后缀：-ate = 名词或形容词
chronic
adj. 慢性的，长期的
A chronic illness or disability lasts for a very long time.
词根：chron = time 时间
后缀：-ic = 形容词
这里联想到cron 表达式
dedicate
v.献身；投身；致力
If you say that someone has dedicated themselves to something, you approve of the fact that they have decided to give a lot of time and effort to it because they think that it is important.
前缀：de- = down 往下
词根：dic = proclaim 宣称
后缀：-ate 动词：做、造成
加入托词魔鬼训练 mini 营，每天拼写 5 个词，已经第 27 天了。
代码的学习
做了一道关于树的练习题，一开始连测试用例都没看明白。
https://leetcode-cn.com/problems/n-ary-tree-preorder-traversal/
看到这个测试用例，懵逼了，这个数组怎么表示的是这样一颗二叉树呢？
接着有被这篇示例误导了：
https://support.leetcode-cn.com/hc/kb/article/1194353/
这篇示例讲的是二叉树，而测试用例是N叉树。
后来，改了几个测试用例，才明白，原来就是对N叉树简单的水平遍历，每层用 null 分开。
蠢啊。
记录一下。
