110 lines
4.7 KiB
C++
110 lines
4.7 KiB
C++
// Source : https://leetcode.com/problems/design-authentication-manager/
|
|
// Author : Hao Chen
|
|
// Date : 2021-03-22
|
|
|
|
/*****************************************************************************************************
|
|
*
|
|
* There is an authentication system that works with authentication tokens. For each session, the user
|
|
* will receive a new authentication token that will expire timeToLive seconds after the currentTime.
|
|
* If the token is renewed, the expiry time will be extended to expire timeToLive seconds after the
|
|
* (potentially different) currentTime.
|
|
*
|
|
* Implement the AuthenticationManager class:
|
|
*
|
|
* AuthenticationManager(int timeToLive) constructs the AuthenticationManager and sets the
|
|
* timeToLive.
|
|
* generate(string tokenId, int currentTime) generates a new token with the given tokenId at
|
|
* the given currentTime in seconds.
|
|
* renew(string tokenId, int currentTime) renews the unexpired token with the given tokenId at
|
|
* the given currentTime in seconds. If there are no unexpired tokens with the given tokenId, the
|
|
* request is ignored, and nothing happens.
|
|
* countUnexpiredTokens(int currentTime) returns the number of unexpired tokens at the given
|
|
* currentTime.
|
|
*
|
|
* Note that if a token expires at time t, and another action happens on time t (renew or
|
|
* countUnexpiredTokens), the expiration takes place before the other actions.
|
|
*
|
|
* Example 1:
|
|
*
|
|
* Input
|
|
* ["AuthenticationManager", "renew", "generate", "countUnexpiredTokens", "generate", "renew",
|
|
* "renew", "countUnexpiredTokens"]
|
|
* [[5], ["aaa", 1], ["aaa", 2], [6], ["bbb", 7], ["aaa", 8], ["bbb", 10], [15]]
|
|
* Output
|
|
* [null, null, null, 1, null, null, null, 0]
|
|
*
|
|
* Explanation
|
|
* AuthenticationManager authenticationManager = new AuthenticationManager(5); // Constructs the
|
|
* AuthenticationManager with timeToLive = 5 seconds.
|
|
* authenticationManager.renew("aaa", 1); // No token exists with tokenId "aaa" at time 1, so nothing
|
|
* happens.
|
|
* authenticationManager.generate("aaa", 2); // Generates a new token with tokenId "aaa" at time 2.
|
|
* authenticationManager.countUnexpiredTokens(6); // The token with tokenId "aaa" is the only
|
|
* unexpired one at time 6, so return 1.
|
|
* authenticationManager.generate("bbb", 7); // Generates a new token with tokenId "bbb" at time 7.
|
|
* authenticationManager.renew("aaa", 8); // The token with tokenId "aaa" expired at time 7, and 8 >=
|
|
* 7, so at time 8 the renew request is ignored, and nothing happens.
|
|
* authenticationManager.renew("bbb", 10); // The token with tokenId "bbb" is unexpired at time 10, so
|
|
* the renew request is fulfilled and now the token will expire at time 15.
|
|
* authenticationManager.countUnexpiredTokens(15); // The token with tokenId "bbb" expires at time 15,
|
|
* and the token with tokenId "aaa" expired at time 7, so currently no token is unexpired, so return 0.
|
|
*
|
|
* Constraints:
|
|
*
|
|
* 1 <= timeToLive <= 10^8
|
|
* 1 <= currentTime <= 10^8
|
|
* 1 <= tokenId.length <= 5
|
|
* tokenId consists only of lowercase letters.
|
|
* All calls to generate will contain unique values of tokenId.
|
|
* The values of currentTime across all the function calls will be strictly increasing.
|
|
* At most 2000 calls will be made to all functions combined.
|
|
******************************************************************************************************/
|
|
|
|
class AuthenticationManager {
|
|
private:
|
|
int ttl;
|
|
set<pair<int, string>> time_set;
|
|
unordered_map<string, int> token_map;
|
|
public:
|
|
AuthenticationManager(int timeToLive):ttl(timeToLive) { }
|
|
|
|
void generate(string tokenId, int currentTime) {
|
|
token_map[tokenId] = currentTime;
|
|
time_set.insert({currentTime, tokenId});
|
|
}
|
|
|
|
void renew(string tokenId, int currentTime) {
|
|
//if the token is not found, or the token is expired
|
|
if (token_map.find(tokenId) == token_map.end() ||
|
|
token_map[tokenId] + ttl <= currentTime ) {
|
|
return;
|
|
}
|
|
time_set.erase({token_map[tokenId], tokenId});
|
|
time_set.insert({currentTime, tokenId});
|
|
token_map[tokenId] = currentTime;
|
|
}
|
|
|
|
int countUnexpiredTokens(int currentTime) {
|
|
return clean(currentTime - ttl);
|
|
}
|
|
|
|
int clean(int expired) {
|
|
|
|
auto it = time_set.begin();
|
|
while(!time_set.empty() && it->first <= expired) {
|
|
token_map.erase(it->second);
|
|
time_set.erase(it);
|
|
it = time_set.begin();
|
|
}
|
|
return time_set.size();
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Your AuthenticationManager object will be instantiated and called as such:
|
|
* AuthenticationManager* obj = new AuthenticationManager(timeToLive);
|
|
* obj->generate(tokenId,currentTime);
|
|
* obj->renew(tokenId,currentTime);
|
|
* int param_3 = obj->countUnexpiredTokens(currentTime);
|
|
*/
|