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Authentication System 🐹

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Problem statement

Develop a session-based authentication system where each user session generates a new token with a specified time-to-live (TTL) expiration. The TTL expiration is calculated as the current time plus the time-to-live seconds. If a token is renewed, the TTL is extended to the time-to-live seconds after the time of the renewal.

There are three types of queries in this system:

  • "generate <token_id> <current_time>": Creates a new token with the given token_id and current_time.
  • "renew <token_id> <current_time>": Renews an unexpired token with the given token_id and current_time. If there is no unexpired token with the specified token_id, the request is ignored.
  • "count <current_time>": Returns the number of unexpired tokens at the given current_time.

    • Note: If a token expires at a specific time and any action is performed at that same time, the token's expiration occurs before any other actions are carried out.

    Function

    getUnexpiredTokens(time_to_live: int, queries: String[][]) → int[]

    Complete the function getUnexpiredTokens in the editor below.

    getUnexpiredTokens has the following parameter(s):

    • 1. int time_to_live: the time to live for a token
    • 2. String[] queries: the queries

    Returns

    int[]: the results from type-3 query in the same order it is given

    Examples

    Example 1

    time_to_live = 5queries = [["generate aaa 1"], ["renew aaa 2"], ["count 6"], ["generate bbb 7"], ["renew aaa 8"], ["renew bbb 10"], ["count 15"]]return = [1, 0]
    The output of the system is [1, 0]. At t = 6, the only unexpired token is "aaa". At t = 15, all tokens have expired, so the count of unexpired tokens is 0.

    Constraints

    Unknwon for now

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    public int[] getUnexpiredTokens(int time_to_live, String[][] queries) {
  // write your code here
}
    time_to_live5
    queries[["generate aaa 1"], ["renew aaa 2"], ["count 6"], ["generate bbb 7"], ["renew aaa 8"], ["renew bbb 10"], ["count 15"]]
    expected[1, 0]
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