LeetCode link first thought the regions which is not surrounded by X is must be started from one side mark all the ‘O’ that stretched from sides with BFS the...

LeetCode link first thought the same as word ladder problem, just need to record paths to the current word solution 1234567891011121314151617181920212223242...

本地网络上容易发现的广告服务，或者发现其他人的广告服务。 主题 本地网络服务（Local Network Services）1class NetService 一个可以通过多播DNS（multicast DNS）广播其可用状态的网络服务。 1protocol NetServiceDelegate 一个定义U...

LeetCode link first thought same as bfs maze problem. build a map to record the distance of each word. solution 12345678910111213141516171819202122232425262...

LeetCode link first thought the same as maze II, using BFS. need to record the path, and update the path at proper time. there’s no need to iterate when the ...

使用标准Internet协议与URL进行交互及与服务端通信。 主题 第一步（First Steps）1class URLSession 一个协调一组相关网络数据传输任务的对象。（An object that coordinates a group of related network data transfer...

LeetCode link first thought Using BFS How to maintain the distance of each position. => Build a int[][] . The first reach of destination may not be the be...

DFS主要使用递归，每次把问题规模减小，但问题本身不变，一直递归到 base case 之后return。 关键点 找到问题相同但规模减小的子问题。 确定共同的参数。 确定base case。 BFS主要使用Queue，每次到一个新节点之后把当前可能的延伸方向放入queue中，每次从queue中取。需要注意...

LeetCode link first thought first check the obvious situation such as the total sum can’t be divided by 4, or smaller than the maximum number * 4 same as the...

管理通过用户的iCloud设备来自动同步的文件及键值对（key-value）数据。 主题 iCloud 存储 (iCloud Storage)1class FileManager 一个给文件系统中的内容提供方便接口的对象。 1protocol FileManagerDelegate 文件管理器（File Man...