Package g1801_1900.s1845_seat_reservation_manager

Class SeatManager

java.lang.Object
g1801_1900.s1845_seat_reservation_manager.SeatManager
public class SeatManager extends java.lang.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 Summary

    Constructors
    Constructor
    Description
    SeatManager(int n)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    reserve()
     
    void
    unreserve(int seatNumber)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • SeatManager

      public SeatManager(int n)

  • Method Details

    • reserve

      public int reserve()

    • unreserve

      public void unreserve(int seatNumber)