What are Data Structures?

Data Structures are the representation of data in memory.

Data structures are a way of organizing and storing data in the memory so that it can be accessed and modified efficiently. Picking the right data structure depends on the specific needs of a problem and the operations that will be performed on the data. Different data structures have different strengths and weaknesses, and the right choice can make the difference between a program that runs in a fraction of a second or one that takes hours to complete.

Classification of Data Structures

Data structures can be broadly classified into two categories:

• Linear Data Structures: Linear data structures are those in which data elements are arranged in a linear sequence. Examples of linear data structures include arrays, linked lists, stacks, and queues.

• Non-linear Data Structures: are those in which data elements are not arranged in a linear sequence. Examples of non-linear data structures include trees, graphs, and hash tables.

Additionally, data structures can also be classified based on the type of operations that can be performed on them:

• Static Data Structures: Static data structures are those in which the size of the data structure is fixed and does not change during the execution of the program. Examples of static data structures include arrays and structures.

• Dynamic Data Structures: Dynamic data structures are those in which the size of the data structure can change during the execution of the program. Examples of dynamic data structures include linked lists, stacks, and queues.

• Homogeneous Data Structures: Homogeneous data structures are those in which all the elements of the data structure are of the same data type. Examples of Homogeneous data structures include arrays and linked lists.

• Heterogeneous Data Structures: Heterogeneous data structures are those in which elements of the data structure are of different data types. Examples of Heterogeneous data structures include trees and graphs.

It’s worth noting that, this classification is not mutually exclusive and a data structure can belong to multiple categories at the same time.

Common Data Structures

Some common data structures include:

• Arrays: A collection of items stored at contiguous memory locations.
• Linked Lists: A linear collection of data elements, called nodes, pointing to the next node by means of a pointer.
• Stacks: A collection of elements, with two main operations: push, which adds an element to the collection, and pop, which removes the most recently added element.
• Queues: A collection of elements, with two main operations: enqueue, which adds an element to the collection, and dequeue, which removes the oldest element.
• Trees: A collection of elements that are organized hierarchically.
• Graphs: A collection of interconnected nodes, where each node may represent an object, and the edges represent relationships or connections between the objects.
• Hash tables: A data structure that allows for fast insertion, deletion, and lookup of elements.

These are some of the most common data structures and there are many more like Heaps, Tries, Bloom filter etc. Choosing the right data structure depends on the specific requirements of the problem and the operations that need to be performed on the data.

If you are interested in learning more about data structures, have a look at this in-depth guide on Data Structures and Algorithms.