**Is Heap a Data Structure or ADT?**

A __heap__ is a __data structure__ that can also be considered as an __abstract data type (ADT)__. It is commonly used to implement priority queues, which are data structures that allow efficient insertion and removal of elements based on their priority. In this article, we will explore the characteristics of a heap and discuss whether it should be classified as a data structure or an ADT.

## The Characteristics of a Heap

A heap is a complete binary tree, meaning that all levels of the tree are completely filled except possibly for the last level, which is filled from left to right. This property ensures that heaps can be efficiently represented using arrays.

In addition to being a complete binary tree, heaps have two main properties:

**The Heap Property:**The values stored in each node must satisfy the heap property. In a*max heap*, for example, the value in each node must be greater than or equal to the values in its children. In a*min heap*, the value in each node must be less than or equal to the values in its children.**The Shape Property:**As mentioned earlier, heaps are complete binary trees.

## Data Structure vs. Abstract Data Type (ADT)

A __data structure__, by definition, refers to the way data is organized and stored in memory, along with operations that can be performed on it. It provides concrete implementation details and focuses on how data is represented and manipulated.

An __abstract data type (ADT)__, on the other hand, refers to a high-level description of a set of operations that can be performed on a data structure, without specifying the implementation details. It focuses on what operations can be performed and what properties they should satisfy, rather than how they are implemented.

Based on these definitions, a heap can be classified as both a data structure and an ADT:

- As a data structure, a heap specifies how the elements are organized in memory (as a complete binary tree) and the operations that can be performed on it (such as insertion, deletion, and retrieval).
- As an ADT, a heap describes the properties that should be satisfied by the data structure (the heap property and the shape property) and the operations that can be performed on it (insertion, deletion, retrieval).

## In Conclusion

A heap is both a data structure and an ADT. Its classification as an ADT emphasizes its abstract nature and focuses on what it should do rather than how it is implemented. However, its classification as a data structure highlights its concrete implementation details and how it is represented in memory.

Understanding this distinction is crucial for programmers as it helps in choosing the appropriate data structures or ADTs based on their requirements and constraints.