LeetCode 260 Single Number III 题解

1.题目：

Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once.

For example:

Given nums = [1, 2, 1, 3, 2, 5], return [3, 5].

LeetCode P283 Move Zeroes 题解

1.题目：

Given an array nums, write a function to move all 0’s to the end of it while maintaining the relative order of the non-zero elements.

For example, given nums = [0, 1, 0, 3, 12], after calling your function, nums should be [1, 3, 12, 0, 0].

Note:

You must do this in-place without making a copy of the array.
Minimize the total number of operations.

Set

Set是一个接口继承自Collection(集合)

Set是一种不包含重复的元素的无序Collection。
Set是接口，自身没有具体实现。

LeetCode P349 Intersection of Two Arrays 题解

1.题目：

Given two arrays, write a function to compute their intersection.

Example:
Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2].

Note:

Each element in the result must be unique.
The result can be in any order.

题意：

输入两个int类型的数组，返回一个数组内容是它们的公共部分，不允许有重复，顺序随意

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LeetCode P226 Invert Binary Tree 题解

1.题目：

Invert a binary tree.

题意：

将一个二叉树反转

LeetCode P104 Maximum Depth of Binary Tree 题解

1.题目：

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

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题意：

找出一个二叉树最长一个分支上面节点的个数

二叉树