Python Coding challenge - Day 444| What is the output of the following Python Code?

 

Code Explanation:

import heapq

Purpose: This line imports Python’s built-in heapq module.

What it does: heapq provides an implementation of the heap queue algorithm, also known as a priority queue.

Note: Heaps in Python using heapq are min-heaps, meaning the smallest element is always at the root (index 0 of the list).

Initialize a list

h = [5, 8, 10]

Purpose: Create a regular list h containing three integers: 5, 8, and 10.

Note: At this point, h is just a plain list — not a heap yet.

Convert the list into a heap

heapq.heapify(h)

Purpose: Transforms the list h into a valid min-heap in-place.

Result: After heapifying, the smallest element moves to index 0.

For h = [5, 8, 10], it's already a valid min-heap, so the structure doesn't visibly change:

h → [5, 8, 10]

Push and Pop in one step

print(heapq.heappushpop(h, 3))

Purpose: Pushes the value 3 into the heap, then immediately pops and returns the smallest item from the heap.

What happens:

Push 3 → temporary heap is [3, 5, 10, 8]

Pop the smallest item → 3 is the smallest, so it's popped.

Final heap → [5, 8, 10] (same as before)

Return value: The popped value, which is 3, is printed.

Final Output:

3