leetcode 1.TwoSum题目: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 exactly one solution, and you may not use the sam 2019-01-03 leetcode 算法 Map
leetcode 102.Binary Tree Level Order Traversal题目:Given a binary tree, return the level order traversal of its nodes’ values. (ie, from left to right, level by level). For example:Given binary tree [3,9,20,null,null,15,7],12345 3 / \9 20 / \ 1 2019-01-02 leetcode 算法 tree