Priority Queue Introduction and Concept in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an empty priority queue using Python's heapq module.

DSA Python

import heapq
pq = [1]

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A[]

B{}

C()

Dset()

Attempts:

3 left

💡 Hint

Common Mistakes

Using a dictionary or set instead of a list to store the priority queue.

Priority queues in Python can be implemented using a list with the heapq module. An empty list [] is used to start the queue.

2fill in blank

medium

Complete the code to add an element with priority 5 to the priority queue.

DSA Python

import heapq
pq = []
heapq.[1](pq, 5)

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Apop

Binsert

Cheappush

Dpush

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop or insert which are not heapq functions for adding elements.

The heappush function adds an element to the heap while maintaining the heap property.

3fill in blank

hard

Fix the error in the code to remove the smallest element from the priority queue.

DSA Python

import heapq
pq = [3, 5, 7]
heapq.heapify(pq)
smallest = heapq.[1](pq)
print(smallest)

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Apopitem

Bpop

Cremove

Dheappop

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop which removes the last element, not the smallest.

The heappop function removes and returns the smallest element from the heap.

4fill in blank

hard

Fill both blanks to create a priority queue from a list and then add a new element 2.

DSA Python

import heapq
pq = [4, 1, 7]
heapq.[1](pq)
heapq.[2](pq, 2)

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

Aheapify

Bheappush

Csorted

Dlist

Attempts:

3 left

💡 Hint

Common Mistakes

Using sorted instead of heapify to create a heap.

heapify converts a list into a heap in-place. Then heappush adds a new element while keeping the heap property.

5fill in blank

hard

Fill all three blanks to pop the smallest element, then push 6, and finally peek at the smallest element without removing it.

DSA Python

import heapq
pq = [3, 8, 5]
heapq.heapify(pq)
smallest = heapq.[1](pq)
heapq.[2](pq, 6)
peek = pq[3]

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

Aheappop

Bheappush

C[0]

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to peek using pop() which removes elements.

heappop removes the smallest element, heappush adds a new element, and accessing pq[0] peeks at the smallest element without removing it.