Deque (double-ended queue) in Data Structures Theory - Mini Project: Build & Apply

Deque (double-ended queue)

📖 Scenario: Imagine you are managing a line of customers waiting for service at a bank. Sometimes customers join the line at the back, and sometimes VIP customers join at the front. Also, customers can leave from either end when served.

🎯 Goal: You will build a simple representation of a deque (double-ended queue) using a list. You will add customers to both ends and remove customers from both ends, simulating how a deque works.

📋 What You'll Learn

Create a list called deque with initial customers 'Alice' and 'Bob'

Create a variable called vip_customer with the value 'Eve'

Add the vip_customer to the front of the deque

Remove the last customer from the deque

💡 Why This Matters

🌍 Real World

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

💼 Career

Understanding deques helps in programming tasks that require flexible data structures, such as managing tasks, undo features, or buffering data streams.

1

Create the initial deque

Create a list called deque with the exact customers 'Alice' and 'Bob' in that order.

Data Structures Theory

# Create the deque list with 'Alice' and 'Bob'
deque = []  # Your code here

Need a hint?

Use square brackets to create a list with two strings: 'Alice' and 'Bob'.

2

Add a VIP customer variable

Create a variable called vip_customer and set it to the string 'Eve'.

Data Structures Theory

deque = ['Alice', 'Bob']
# Create vip_customer variable with value 'Eve'
vip_customer = ''  # Your code here

Need a hint?

Assign the string 'Eve' to the variable vip_customer.

3

Add VIP customer to the front of the deque

Use the insert method on deque to add vip_customer at the front (index 0).

Data Structures Theory

deque = ['Alice', 'Bob']
vip_customer = 'Eve'
# Insert vip_customer at the front of deque
# Your code here

Need a hint?

Use deque.insert(0, vip_customer) to add Eve at the front.

4

Remove the last customer from the deque

Use the pop method on deque without arguments to remove the last customer.

Data Structures Theory

deque = ['Alice', 'Bob']
vip_customer = 'Eve'
deque.insert(0, vip_customer)
# Remove the last customer from deque
# Your code here

Need a hint?

Use deque.pop() to remove the last item from the list.