TinyURL是一种URL简化服务， 比如：当你输入一个URL https://leetcode.com/problems/design-tinyurl 时，它将返回一个简化的URL http://tinyurl.com/4e9iAk.
要求：设计一个 TinyURL 的加密 encode 和解密 decode 的方法。你的加密和解密算法如何设计和运作是没有限制的，你只需要保证一个URL可以被加密成一个TinyURL，并且这个TinyURL可以用解密方法恢复成原本的URL。
class Solution {
private:
unordered_map
const string str = "1234567890qwertyuiopasdlkjfhgmznxcbvZXMNCBVLAKSJDHFGQWERUIOTP";
public:
// Encodes a URL to a shortened URL.
string encode(string longUrl) {
string encoded;
srand(time(NULL));
while (true) {
for (int i = 0; i < 6; ++i) {
encoded.push_back(str[rand() % str.size()]);
}
if (!dict[encoded].size()) {
break;
}
}
int index = longUrl.size() - 1;
string ss;
while (index >= 0 && longUrl[index] != '/') {
ss.push_back(longUrl[index]);
index -= 1;
}
reverse(ss.begin(), ss.end());
string temp = longUrl.substr(0, index + 1);
dict[encoded] = ss;
long_ulr[ss] = temp;
return encoded;
}
// Decodes a shortened URL to its original URL.
string decode(string shortUrl) {
return long_ulr[dict[shortUrl]] + dict[shortUrl];
}
};
// Your Solution object will be instantiated and called as such:
// Solution solution;
// solution.decode(solution.encode(url));