535. Encode and Decode TinyURL 长短URL
[抄题]:
TinyURL is a URL shortening service where you enter a URL such as https://leetcode.com/problems/design-tinyurl
and it returns a short URL such as http://tinyurl.com/4e9iAk
.
Design the encode
and decode
methods for the TinyURL service. There is no restriction on how your encode/decode algorithm should work. You just need to ensure that a URL can be encoded to a tiny URL and the tiny URL can be decoded to the original URL.
[暴力解法]:
时间分析:
空间分析:
[优化后]:
时间分析:
空间分析:
[奇葩输出条件]:
[奇葩corner case]:
[思维问题]:
完全不知道用什么数据结构来实现
[一句话思路]:
短URL必须是在当前的arraylist中,自己生成的才可以
[输入量]:空: 正常情况:特大:特小:程序里处理到的特殊情况:异常情况(不合法不合理的输入):
[画图]:
[一刷]:
[二刷]:
[三刷]:
[四刷]:
[五刷]:
[五分钟肉眼debug的结果]:
[总结]:
同一个arraylist中自产自销就可以,不是就不行
[复杂度]:Time complexity: O(n) Space complexity: O(n)
[英文数据结构或算法,为什么不用别的数据结构或算法]:
ArrayList动态添加
[关键模板化代码]:
[其他解法]:
[Follow Up]:
[LC给出的题目变变变]:
[代码风格] :
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
public class Codec { List<String> urls = new ArrayList<String>(); // Encodes a URL to a shortened URL. public String encode(String longUrl) { urls.add(longUrl); return String.valueOf(urls.size() - 1); } // Decodes a shortened URL to its original URL. public String decode(String shortUrl) { int index = Integer.valueOf(shortUrl); return (index <= urls.size()) ? urls.get(index) : ""; } } // Your Codec object will be instantiated and called as such: // Codec codec = new Codec(); // codec.decode(codec.encode(url));