James Pan

原题网址：https://leetcode.com/problems/serialize-and-deserialize-binary-tree/Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in

原题网址：https://leetcode.com/problems/flatten-nested-list-iterator/Given a nested list of integers, implement an iterator to flatten it.Each element is either an integer, or a list -- whose ele