摘要：
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representatio... 阅读全文
摘要：
A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.Return a deep copy ... 阅读全文
摘要：
Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.top-down还是o(nlgn)。自己没有细想，不过查了一下，发现还是有o(n)... 阅读全文