摘要：
Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum 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. 思路：才用快慢指针，找到中间节点，然后递归处理。 accepted code： 阅读全文