Challenge #4 — Problem Solving Challenge

Below is a problem solving scenario. You may solve it in any of the following languages:

• TypeScript/JavaScript
• Java
• Python
• C#

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Seat Reservation System Challenge

Scenario

A movie theatre has N seats, numbered from 1 to N. You're tasked with implementing a seat reservation system that performs K operations, each of which:

1. Reserves the smallest-numbered unreserved seat, or
2. Cancels a reservation for a specific seat.

After each reservation (not cancellation), the system must return the seat number that was reserved.

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Objective

Implement a function that processes the operations efficiently and returns the list of reserved seat numbers in the order they were made.

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Input Format

• N → Integer: Number of seats (1-indexed, from 1 to N)

• K → Integer: Number of operations

• seat → Integer array of size K

  • If seat[i] == 0, reserve the smallest available seat
  • If seat[i] > 0, cancel the reservation for seat number seat[i]

Example:

N = 5
K = 6
seat = [0, 0, 0, 2, 1, 0]

Output:

[1, 2, 3, 1]

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Output Format

Print an array containing the reserved seat numbers in order. Only include seat numbers that were actually reserved (i.e., ignore cancellations).

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Constraints

• 1 < N < 10^5
• 1 < K < 10^5
• 0 <= seat[i] <= N
• Each reservation guarantees an unreserved seat is available.
• Each cancellation guarantees that the seat was reserved.

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Example Function Signature

In Java:

public static List<Integer> seatReservation(int N, int K, int[] seat)

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Submission Instructions

Please see challenge-4/seat-reservations-submissions/README.md