2022-06-29

[Zheaoli]

2022-06-29

[SaraadKun]

535. TinyURL 的加密与解密

    //随机hash实现
    Map<String, String> db = new HashMap<>();
    Map<String, String> cache = new HashMap<>();
    Random rd = new Random();
    final int k = 6;
    final String base = "http://tinyurl.com/";
    final char[] dict = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();

    // Encodes a URL to a shortened URL.
    public String encode(String longUrl) {
        if (cache.containsKey(longUrl))
            return base + cache.get(longUrl);
        String shortUrl;
        do {
            char[] chs = new char[k];
            for (int i = 0; i < k; i++) {
                chs[i] = dict[rd.nextInt(dict.length)];
            }
            shortUrl = new String(chs);
        } while(db.containsKey(shortUrl));
        db.put(shortUrl, longUrl);
        cache.put(longUrl, shortUrl);
        return base + shortUrl;
    }

    // Decodes a shortened URL to its original URL.
    public String decode(String shortUrl) {
        return db.get(shortUrl.substring(shortUrl.lastIndexOf("/") + 1));
    }

}

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WeChat: Saraad

[dreamhunter2333]

#include <iostream>
#include <unordered_map>
using namespace std;
/*
 * @lc app=leetcode.cn id=535 lang=cpp
 *
 * [535] TinyURL 的加密与解密
 */

// @lc code=start
class Solution
{
private:
    unordered_map<int, string> data;
    int max_id = 0;

public:
    // Encodes a URL to a shortened URL.
    string encode(string longUrl)
    {
        max_id++;
        data[max_id] = longUrl;
        return "http://tinyurl.com/" + to_string(max_id);
    }

    // Decodes a shortened URL to its original URL.
    string decode(string shortUrl)
    {
        string data_id = shortUrl;
        size_t pos;
        string delimiter = "/";
        while ((pos = data_id.find(delimiter)) != string::npos)
        {
            data_id.erase(0, pos + delimiter.length());
        }
        return data[std::stoi(data_id)];
    }
};

// @lc code=end
int main()
{
    string url = "https://leetcode.com/problems/design-tinyurl";
    Solution solution;
    return url != solution.decode(solution.encode(url));
}

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