Summary

小技巧 for List：

1. Dummy Head Node
2. Fast-Slow Pointers

List 的题目相对比较简单，值得一做的题目：

• https://leetcode.com/problems/sort-list/description/
  需要回顾总结 Sorting Algorithms
• https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/description/