题目描述：
LeetCode 331. Verify Preorder Serialization of a Binary Tree
One way to serialize a binary tree is to use pre-oder traversal. When we encounter a non-null node, we record the node's value. If it is a null node, we ...
LeetCode 331. Verify Preorder Serialization of a Binary Tree
One way to serialize a binary tree is to use pre-oder traversal. When we encounter a non-null node, we record the node's value. If it is a null node, we ...