先科普一下什么叫斐波那契数列，以下内容摘自百度百科： 斐波那契数列（Fibonacci sequence），又称黄金分割数列、因意大利数学家列昂纳多·斐波那契（Leonardoda Fibonacc ...

Given preorder and inorder traversal of a tree, construct the binary tree. You ...

Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a b ...

如题，谷歌两轮背靠背电面。两轮都是废话不多说直奔coding，虽然第一轮的中国大哥还是花了一点点时间了解了一下我的背景、毕业时间、research方向。说好的research面呢？ 中国大哥出的题: ...

Given a set of candidate numbers (candidates) (without duplicates) and a target number (target), fin ...

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For examp ...

You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb ...

Recursion: 返回的时候返回lca和depth，每个node如果有大于一个子节点的depth相同就返回这个node，如果有一个子节点depth更深就返回个子节点lca，这个 ...