Data structures are a way of organizing and storing data in a computer’s memory or storage system. They provide a means for efficiently accessing and manipulating data to perform various operations. Different data structures are designed to handle different types of data and operations efficiently.

Here are some commonly used data structures:

1. Array: An array is a sequential collection of elements of the same type, stored in contiguous memory locations. It allows constant-time access to elements using their indices.
2. Linked List: A linked list is a collection of nodes, where each node contains data and a reference (or link) to the next node. It allows efficient insertion and deletion of elements but requires sequential traversal for access.
3. Stack: A stack is a Last-In-First-Out (LIFO) data structure that allows adding and removing elements only from one end, called the top. It follows the principle of “last in, first out.”
4. Queue: A queue is a First-In-First-Out (FIFO) data structure that allows adding elements to the rear and removing elements from the front. It follows the principle of “first in, first out.”
5. Tree: A tree is a hierarchical data structure consisting of nodes connected by edges. It has a root node and zero or more child nodes, forming a parent-child relationship. Trees are commonly used for hierarchical representation and searching operations.
6. Heap: A heap is a complete binary tree that satisfies the heap property, which specifies the relationship between parent and child nodes. It is commonly used to efficiently find the minimum or maximum element (depending on the heap type) in constant time.
7. Hash Table: A hash table (or hash map) is a data structure that stores data in an associative manner, using key-value pairs. It uses a hash function to compute an index (hash) for each key and stores the value at that index. Hash tables provide efficient average-case lookup, insertion, and deletion operations.
8. Graph: A graph is a non-linear data structure consisting of a set of vertices (or nodes) and edges connecting these vertices. Graphs are used to represent relationships between objects and are useful for solving problems related to networks, paths, and connectivity.

These are just a few examples of data structures, and there are many more variations and advanced structures available. The choice of data structure depends on the specific requirements of the problem at hand and the efficiency needed for different operations.