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Implement a Queue Using a List

Certification: Advanced Level Accuracy: 100% Submissions: 2 Points: 10

Create a Python class called Queue that implements a queue data structure using a list. The class should support standard queue operations such as enqueue, dequeue, peek, is_empty, and size. The queue should follow the First-In-First-Out (FIFO) principle.

Example 1
    
  
  • Input: queue = Queue()
    • 
  
  • Operations: queue.enqueue(10)
    • 
  
  • Operations: queue.enqueue(20)
    • 
  
  • Operations: queue.dequeue()
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  • Operations: queue.peek()
    • 
  
  • Output: 10, 20
    • 
  
  • Explanation:
    
      
      
    • Step 1: Create a Queue instance.
      • 
      
    • Step 2: Enqueue two values.
      • 
      
    • Step 3: Dequeue the first value (10).
      • 
      
    • Step 4: Peek at the next value (20).
      • 
    
    
  
    •
Example 2
    
  
  • Input: queue = Queue()
    • 
  
  • Operations: queue.enqueue("apple")
    • 
  
  • Operations: queue.enqueue("banana")
    • 
  
  • Operations: queue.is_empty()
    • 
  
  • Operations: queue.size()
    • 
  
  • Operations: queue.peek()
    • 
  
  • Operations: queue.dequeue()
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  • Operations: queue.size()
    • 
  
  • Output: False, 2, "apple", 1
    • 
  
  • Explanation:
    
      
      
    • Step 1: Create a Queue instance.
      • 
      
    • Step 2: Enqueue two values.
      • 
      
    • Step 3: Check if queue is empty (False).
      • 
      
    • Step 4: Get queue size (2).
      • 
      
    • Step 5: Peek at first value ("apple").
      • 
      
    • Step 6: Dequeue first value ("apple").
      • 
      
    • Step 7: Get new queue size (1).
      • 
    
    
  
    •
Constraints
    
  
  • The queue can contain elements of any data type.
    • 
  
  • Time Complexity: O(1) for all operations except dequeue which could be O(n).
    • 
  
  • Space Complexity: O(n) where n is the number of elements in the queue.
    • 
  
  • Dequeue and peek operations on an empty queue should be handled gracefully.
    •
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Hint
Solution

Solution Hints

    
        
  • Use a Python list to store the queue elements
    • 
        
  • For enqueue, use list.append()
    • 
        
  • For dequeue, consider using list.pop(0) or collections.deque for better performance
    • 
        
  • Implement proper error handling for operations on an empty queue
    • 
        
  • Consider implementing a max_size parameter (optional)
    •

Steps to solve by this approach:

 Step 1: Create a Queue class with a list to store queue elements.

 Step 2: Implement enqueue method to add items to the end of the queue.

 Step 3: Implement dequeue method to remove and return the first item.

 Step 4: Implement helper methods like peek, is_empty, and size.

 Step 5: Test the implementation with various operations.

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