I was a little bored recently and thought to myself, why not implement a Heap data structure in C# from scratch just to keep my mind sharp? 🙂I still remember the first time I came across this data structure at university — I was immediately fascinated. What a clever idea: representing a binary tree using an array and applying a simple invariant to build an in-place, stable sorting algorithm like HeapSort.Now, if you ask most engineers whether they could implement a heap from scratch, they'd probably say no — and that’s perfectly fine. But you don’t want to be just an average engineer, right?If you understand what a Heap is and how to use simple index math to navigate the tree up and down, you can figure out how to implement it — even if you don’t remember the details. Memorizing an algorithm is rarely helpful. Instead, focus on understanding the core concept. Once you do, you’ll find it surprisingly easy to reimplement it whenever needed.IMPORTANT: If you're solving a problem in .NET and need a heap, I strongly recommend using the built-in PriorityQueue class. It’s backed by a quaternary min-heap and optimized for performance. Still, it’s valuable to understand how it works under the hood — and you'll be surprised how few lines of modern C# it takes to implement your own.Happy C# coding!