Package g1801_1900.s1845_seat_reservation_manager

Class SeatManager

  • public class SeatManager
extends Object
    1845 - Seat Reservation Manager.

    Medium

    Design a system that manages the reservation state of n seats that are numbered from 1 to n.

    Implement the SeatManager class:

    • SeatManager(int n) Initializes a SeatManager object that will manage n seats numbered from 1 to n. All seats are initially available.
    • int reserve() Fetches the smallest-numbered unreserved seat, reserves it, and returns its number.
    • void unreserve(int seatNumber) Unreserves the seat with the given seatNumber.

    Example 1:

    Input [“SeatManager”, “reserve”, “reserve”, “unreserve”, “reserve”, “reserve”, “reserve”, “reserve”, “unreserve”] [[5], [], [], [2], [], [], [], [], [5]]

    Output: [null, 1, 2, null, 2, 3, 4, 5, null]

    Explanation:

    SeatManager seatManager = new SeatManager(5); // Initializes a SeatManager with 5 seats.

    seatManager.reserve(); // All seats are available, so return the lowest numbered seat, which is 1.

    seatManager.reserve(); // The available seats are [2,3,4,5], so return the lowest of them, which is 2.

    seatManager.unreserve(2); // Unreserve seat 2, so now the available seats are [2,3,4,5].

    seatManager.reserve(); // The available seats are [2,3,4,5], so return the lowest of them, which is 2.

    seatManager.reserve(); // The available seats are [3,4,5], so return the lowest of them, which is 3.

    seatManager.reserve(); // The available seats are [4,5], so return the lowest of them, which is 4.

    seatManager.reserve(); // The only available seat is seat 5, so return 5.

    seatManager.unreserve(5); // Unreserve seat 5, so now the available seats are [5].

    Constraints:

    • 1 <= n <= 105
    • 1 <= seatNumber <= n
    • For each call to reserve, it is guaranteed that there will be at least one unreserved seat.
    • For each call to unreserve, it is guaranteed that seatNumber will be reserved.
    • At most 105 calls in total will be made to reserve and unreserve.

    • Constructor Detail

      • SeatManager

        public SeatManager​(int n)

    • Method Detail

      • reserve

        public int reserve()

      • unreserve

        public void unreserve​(int seatNumber)