**What Is Graph in Non Linear Data Structure?**

In computer science, a graph is a non-linear data structure that consists of a set of nodes (also known as vertices) and a set of edges connecting these nodes. It is used to represent relationships between different entities or objects in a network.

## Nodes and Edges

A graph is composed of two main components:

**Nodes:**Nodes are the fundamental building blocks of a graph. Each node represents an entity or an object, and it can store additional information associated with it. For example, in a social network graph, each node can represent a person, and the additional information can include their name, age, and interests.**Edges:**Edges are the connections between nodes.They represent relationships between entities in the graph. An edge can be directed or undirected, indicating the directionality of the relationship. For example, in a friendship graph, an undirected edge connects two people who are friends with each other.

## Types of Graphs

There are various types of graphs based on their characteristics:

**Directed Graph (Digraph):**In a directed graph, each edge has a specific direction. The relationship between two nodes is one-way. For example, if node A is connected to node B with an edge, you can go from A to B but not from B to A.**Undirected Graph:**In an undirected graph, edges have no specific direction. The relationship between two nodes is bidirectional.For example, if node A is connected to node B with an edge, you can go from A to B and from B to A.

**Weighted Graph:**In a weighted graph, each edge has a weight or cost associated with it. It represents the strength or distance between two nodes. For example, in a transportation network, the weight of an edge can represent the distance between two cities.**Cyclic Graph:**In a cyclic graph, there is at least one path that starts from a node and returns to the same node by following a sequence of edges. Cycles can cause infinite loops when traversing the graph.**Acyclic Graph:**In an acyclic graph, there are no cycles. It means that there is no path that starts from a node and returns to the same node by following a sequence of edges.

## Graph Operations

Graphs support various operations for manipulating and analyzing the underlying data:

**Add Node:**Adds a new node to the graph.**Add Edge:**Connects two nodes with an edge in the graph.**Delete Node:**Removes a node from the graph along with all its associated edges.**Delete Edge:**Removes an edge between two nodes in the graph.**Traverse Graph:**Visits all the nodes in the graph in a specific order. Common traversal algorithms are depth-first search (DFS) and breadth-first search (BFS).

## Applications of Graphs

The concept of graphs has numerous applications in various fields:

**Social Networks:**Graphs are widely used to model social networks, where nodes represent individuals and edges represent connections between them.**Routing Algorithms:**Graphs are used in routing algorithms to find the shortest path between two nodes in a network.**Recommendation Systems:**Graph-based recommendation systems analyze connections between users and items to provide personalized recommendations.**Network Analysis:**Graphs help analyze the structure and behavior of complex networks, such as communication networks or biological networks.

In conclusion, a graph is a powerful non-linear data structure that allows us to model and represent relationships between entities or objects. With its various types, operations, and applications, graphs have become an essential tool in computer science and beyond.