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 an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have ex 阅读全文

摘要： Design and implement a TwoSum class. It should support the following operations:add and find. add - Add the number to an internal data structure.find 阅读全文