1797. 设计一个验证系统题目： https://leetcode.cn/problems/design-authen

题目：
leetcode.cn/problems/de… 算法：
方法一：hash table
这种题目做100遍也不能提高了，搞点有难度的

type AuthenticationManager struct {
    TimeToLive int 
    TokenExpireTime map[string]int
}


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


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


func (this *AuthenticationManager) Renew(tokenId string, currentTime int)  {
    if t, ok := this.TokenExpireTime[tokenId]; ok {
        if currentTime < t {
            this.TokenExpireTime[tokenId] = currentTime + this.TimeToLive
        }
    }
}

// 二分查找
func (this *AuthenticationManager) CountUnexpiredTokens(currentTime int) int {
    count := 0
    for _, t := range this.TokenExpireTime {
        if currentTime < t {
            count ++
        }
    }
    return count
}