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Queue using Arrays

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 8

Write a JavaScript program to implement a Queue data structure using arrays. The queue should support basic operations like enqueue (add element), dequeue (remove element), front (get front element), and isEmpty (check if queue is empty).

Example 1
    
  
  • Input: Operations: ["enqueue", "enqueue", "front", "dequeue", "isEmpty"], Values: [1, 2, null, null, null]
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  • Output: [null, null, 1, 1, false]
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  • Explanation: 
    • enqueue(1) - Add 1 to the queue. Queue: [1].
    • enqueue(2) - Add 2 to the queue. Queue: [1, 2]. 
    • front() - Return front element which is 1. 
    • Queue: [1, 2]. dequeue() - Remove and return front element 1. 
    • Queue: [2]. isEmpty() - Check if queue is empty. 
    • Returns false since queue has element 2.
    •
Example 2
    
  
  • Input: Operations: ["enqueue", "dequeue", "isEmpty", "front"], Values: [5, null, null, null]
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  • Output: [null, 5, true, null]
    • 
  
  • Explanation: 
    • enqueue(5) - Add 5 to the queue. 
    • Queue: [5]. dequeue() - Remove and return front element 5. 
    • Queue: []. isEmpty() - Check if queue is empty. 
    • Returns true since queue is empty. 
    • front() - Try to get front element of empty queue. 
    • Returns null or undefined.
    •
Constraints
    
  
  • 1 ≤ operations.length ≤ 1000
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  • -1000 ≤ value ≤ 1000 for enqueue operations
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  • At most 300 calls will be made to enqueue and dequeue
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  • All operations are valid (no dequeue or front on empty queue)
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  • Time Complexity: O(1) for all operations
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  • Space Complexity: O(n) where n is number of elements
    •
ArraysQueuePwCSwiggy
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Hint
Solution

Solution Hints

    
  
  • Use an array to store queue elements and maintain front and rear pointers
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  • Enqueue operation adds element at the rear of the queue
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  • Dequeue operation removes element from the front of the queue
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  • Keep track of the size of the queue for isEmpty operation
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  • Handle edge cases like empty queue for front and dequeue operations
    • 
  
  • Consider using circular array approach for better space utilization
    •

Steps to solve by this approach:

 Step 1: Initialize a Queue class with an array and front/rear index pointers.

 Step 2: Implement enqueue method to add elements at the rear index position.

 Step 3: Increment rear index after adding each element to maintain queue order.

 Step 4: Implement dequeue method to remove element from front index position.

 Step 5: Increment front index after removing element and return the removed value.

 Step 6: Implement front method to return element at front index without removal.

 Step 7: Implement isEmpty method by comparing front and rear indices.

 Step 8: Handle edge cases for empty queue in dequeue and front operations.

Submitted Code :