The Heap sort algorithm is widely used because of its efficiency. Heap sort works by transforming the list of items to be sorted into a heap data structure, a binary tree with heap properties. In a binary tree, every node has, at most, two descendants. A node possesses the heap property when none of its descendants have greater values than itself. The largest element of the heap is removed and inserted into the sorted list. The remaining sub-tree is transformed into a heap again. This process is repeated until no elements remain. Successive removals of the root node after each rebuilding of the heap produces the final sorted list of items.

## Efficiency

The Heap sort algorithm is very efficient. While other sorting algorithms may grow exponentially slower as the number of items to sort increase, the time required to perform Heap sort increases logarithmically. This suggests that Heap sort is particularly suitable for sorting a huge list of items. Furthermore, the performance of Heap sort is optimal. This implies that no other sorting algorithms can perform better in comparison.

## Memory Usage

The Heap sort algorithm can be implemented as an in-place sorting algorithm. This means that its memory usage is minimal because apart from what is necessary to hold the initial list of items to be sorted, it needs no additional memory space to work. In contrast, the Merge sort algorithm requires more memory space. Similarly, the Quick sort algorithm requires more stack space due to its recursive nature.

## Simplicity

The Heap sort algorithm is simpler to understand than other equally efficient sorting algorithms. Because it does not use advanced computer science concepts such as recursion, it is also easier for programmers to implement correctly.

## Consistency

The Heap sort algorithm exhibits consistent performance. This means it performs equally well in the best, average and worst cases. Because of its guaranteed performance, it is particularly suitable to use in systems with critical response time.

#### References

- University of Maryland University College: Interactive Data Structure Visualizations -- Heap Sort
- Flensburg University of Applied Science: Heapsort
- Stony Brook University: Priority Queues and Heapsort Lecture 18; Steven S. Skiena; October 2009
- aihorizon.com: Heap Trees Part 2
- University of Auckland: Comparing Quick and Heap Sorts

#### Photo Credits

- Thinkstock/Comstock/Getty Images