Deque Quick Start

Description

A deque is a linear data structure that supports appending and popping elements from both ends, with a fixed capacity.

Import class

from dsa.deque import Deque  # or the appropriate Deque class

Creation

Create a deque with a default capacity of 10 elements:

d = Deque()

Create a deque with a capacity of 100 elements:

d = Deque(100)

Append left

Append an element to the left of the deque. Raises an exception when the deque is full.

d.append_left(10)  # Append 10 to the left

Append right

Append an element to the right of the deque. Raises an exception when the deque is full.

d.append_right(20)  # Append 20 to the right

Pop left

Remove and return the element from the left of the deque. Raises an exception if the deque is empty.

value = d.pop_left()  # Pop from the left

Pop right

Pop an element from right the deque. Raise an exception if the deque is empty.

value = d.pop_right()  # Pop from the right

Peek left

Get the element at the left of the deque without removing it. Raises an exception if the deque is empty.

value = d.peek_left()  # Peek at the left

Peek right

Get the element at the right of the deque without removing it. Raises an exception if the deque is empty.

value = d.peek_right()  # Peek at the right

Printing Contents

Use print() to print the elements of the dequeue.

d = Deque()
d.push_front(1)
d.push_front(2)
d.push_back(3)
print(d)

Outputs the following:

[2, 1, 3] Count: 3 Capacity: 10