Queue operations (enqueue, dequeue) in Data Structures Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add an element to the end of the queue.

Data Structures Theory

queue.[1](element)

Drag options to blanks, or click blank then click option'

Adequeue

Bappend

Cenqueue

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using dequeue or pop which remove elements instead of adding.

In many programming languages, adding an element to the end of a list or queue is done using append. This simulates the enqueue operation.

2fill in blank

medium

Complete the code to remove the first element from the queue.

Data Structures Theory

removed = queue.[1](0)

Drag options to blanks, or click blank then click option'

Aappend

Benqueue

Cdequeue

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using append which adds elements instead of removing.

Using pop(0) removes the first element from the list, simulating the dequeue operation in a queue.

3fill in blank

hard

Fix the error in the code to correctly remove the first element from the queue.

Data Structures Theory

removed = queue.[1](0)

Drag options to blanks, or click blank then click option'

Aenqueue

Bdequeue

Cpop

Dappend

Attempts:

3 left

💡 Hint

Common Mistakes

Using enqueue or append which add elements instead of removing.

Using pop(0) removes the first element from the list, simulating the dequeue operation in a queue.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each element to its position in the queue.

Data Structures Theory

{element: index for index, element in enumerate(queue) if index [1] [2]

Drag options to blanks, or click blank then click option'

A<

B5

C>

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators or numbers that don't filter correctly.

This comprehension creates a dictionary of elements with their indexes only if the index is less than 5.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase elements to their indexes if the index is greater than 2.

Data Structures Theory

{ [1]: [2] for [3], element in enumerate(queue) if [3] > 2 }

Drag options to blanks, or click blank then click option'

Aelement.upper()

Belement

Cindex

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up element and index variables or forgetting to convert to uppercase.

The comprehension maps the uppercase version of each element to its index, filtering only elements with index greater than 2.