Double Ended Queue Deque in DSA Python - Build from Scratch

Double Ended Queue (Deque) Operations

📖 Scenario: Imagine you are managing a line of customers waiting for service at a store. Sometimes customers join the line at the front (priority customers), and sometimes at the back (regular customers). You also serve customers from both ends depending on the situation.

🎯 Goal: You will create a double ended queue (deque) using a Python list, add customers to both ends, remove customers from both ends, and finally display the current state of the queue.

📋 What You'll Learn

Create a deque with initial customers

Add customers to the front and back of the deque

Remove customers from the front and back of the deque

Print the final state of the deque showing the order of customers

💡 Why This Matters

🌍 Real World

Deques are used in real life to manage lines where people can join or leave from both ends, like customer service lines or task scheduling.

💼 Career

Understanding deques helps in jobs involving data processing, scheduling, and designing efficient algorithms for real-time systems.

1

Create the initial deque

Create a list called deque with these exact customers in order: 'Alice', 'Bob', 'Charlie'

DSA Python

# Create the initial deque with customers
# Your code here

Hint

Use a Python list with the exact names in the given order.

2

Add customers to both ends

Add 'Diana' to the front of deque using insert(0, 'Diana') and add 'Evan' to the back of deque using append('Evan')

DSA Python

deque = ['Alice', 'Bob', 'Charlie']
# Add 'Diana' to the front and 'Evan' to the back
# Your code here

Hint

Use insert(0, 'Diana') to add at front and append('Evan') to add at back.

3

Remove customers from both ends

Remove the customer from the front of deque using pop(0) and remove the customer from the back of deque using pop()

DSA Python

deque = ['Alice', 'Bob', 'Charlie']
deque.insert(0, 'Diana')
deque.append('Evan')
# Remove one customer from front and one from back
# Your code here

Hint

Use pop(0) to remove from front and pop() to remove from back.

4

Print the final deque state

Print the deque list to show the current order of customers

DSA Python

deque = ['Alice', 'Bob', 'Charlie']
deque.insert(0, 'Diana')
deque.append('Evan')
deque.pop(0)
deque.pop()
# Print the deque
# Your code here

Hint

Use print(deque) to display the list.