1797-DesignAuthenticationManager.go

package main

// 1797. Design Authentication Manager
// 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:
// <img src="https://assets.leetcode.com/uploads/2021/02/25/copy-of-pc68_q2.png" />
// 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.

import "fmt"

type AuthenticationManager struct {
    mp   map[string]int
    life int
}

func Constructor(timeToLive int) AuthenticationManager {
    return AuthenticationManager{ make(map[string]int), timeToLive, }
}

func (this *AuthenticationManager) Generate(tokenId string, currentTime int) {
    this.mp[tokenId] = currentTime + this.life
}

func (this *AuthenticationManager) Renew(tokenId string, currentTime int) {
    if _, ok := this.mp[tokenId]; ok {
        if this.mp[tokenId] > currentTime {
            this.mp[tokenId] = currentTime + this.life
        }
    }
}

func (this *AuthenticationManager) CountUnexpiredTokens(currentTime int) int {
    cnt := 0
    for _, v := range this.mp {
        if v > currentTime {
            cnt++
        }
    }
    return cnt
}

/**
 * Your AuthenticationManager object will be instantiated and called as such:
 * obj := Constructor(timeToLive);
 * obj.Generate(tokenId,currentTime);
 * obj.Renew(tokenId,currentTime);
 * param_3 := obj.CountUnexpiredTokens(currentTime);
 */

func main() {
    // AuthenticationManager authenticationManager = new AuthenticationManager(5); // Constructs the AuthenticationManager with timeToLive = 5 seconds.
    obj := Constructor(5)
    fmt.Println(obj)
    // authenticationManager.renew("aaa", 1); // No token exists with tokenId "aaa" at time 1, so nothing happens.
    obj.Renew("aaa", 1)
    fmt.Println(obj)
    // authenticationManager.generate("aaa", 2); // Generates a new token with tokenId "aaa" at time 2.
    obj.Generate("aaa", 1)
    fmt.Println(obj)
    // authenticationManager.countUnexpiredTokens(6); // The token with tokenId "aaa" is the only unexpired one at time 6, so return 1.
    fmt.Println(obj.CountUnexpiredTokens(6)) // "aaa"
    fmt.Println(obj)
    // authenticationManager.generate("bbb", 7); // Generates a new token with tokenId "bbb" at time 7.
    obj.Generate("bbb", 7)
    fmt.Println(obj)
    // 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.
    obj.Renew("aaa", 8)
    fmt.Println(obj)
    // 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.
    obj.Renew("bbb", 10)
    fmt.Println(obj)
    // 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.
    fmt.Println(obj.CountUnexpiredTokens(15)) // "bbb"
    fmt.Println(obj)
}