摘要：
You are given the root of a binary search tree (BST) and an integer val. Find the node in the BST that the node's value equals val and return the subt 阅读全文
摘要：
Given the root of an n-ary tree, return the preorder traversal of its nodes' values. Nary-Tree input serialization is represented in their level order 阅读全文
摘要：
Given a n-ary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest le 阅读全文