Day 21MediumCustom

Heap Sort (Implementation)

Priority Queue / HeapifySolved Nov 18, 2025

Asked in interviews at

5 in the last 6 months

Google
Bloomberg
Amazon

Microsoft

Problem Description

Given an array of integers, sort the array using the Heap Sort algorithm. This algorithm is an in-place comparison-based sort that uses a Binary Heap data structure.

Solve it yourself before you look

Reading the solution first feels like progress, but it makes the next similar problem — and the interview version — much harder, because you skipped the part where you figure it out. Give it an honest 20–30 minutes. Stuck? Re-read the pattern, watch the concept video, or try the brute force first.

Hidden: approach · solution code

#sorting#heap#in-place

Revising this one?

→Solve it from memory before peeking
→Say the pattern out loud, not just the code
→Explain it like you would to a friend
→Try it again in a different language