# What Is Graph in Data Structure Algorithm?

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Heather Bennett

What Is Graph in Data Structure Algorithm?

A graph is a popular data structure that represents a collection of interconnected nodes, often referred to as vertices. These nodes are connected by edges, which represent the relationships or connections between the vertices. Graphs are widely used in various fields such as computer science, mathematics, and network analysis due to their ability to model complex relationships and solve a wide range of problems.

## Vertices and Edges

In a graph, vertices can be represented using circles or squares, while edges are represented by lines or arrows connecting the vertices. Each vertex can be labeled with specific information relevant to the problem being solved.

Example: Let’s consider a social network where each person is represented by a vertex, and friend relationships are represented by edges connecting the vertices. In this case, the vertices would contain information about each person such as their name, age, and location.

## Types of Graphs

There are several types of graphs based on their characteristics and properties. The two main categories are:

• Directed Graph (Digraph): In a directed graph, each edge has a specific direction associated with it. This means that the relationship between two vertices is one-way.
• Undirected Graph: In an undirected graph, edges do not have any specific direction associated with them. The relationship between two vertices is bidirectional.

In addition to directed and undirected graphs, there are other types of graphs that you may encounter:

• Weighted Graph: In a weighted graph, each edge has an associated weight or cost. These weights can represent various quantities such as distance, time, or cost.
• Cyclic Graph: A cyclic graph contains a cycle, which is a path that starts and ends at the same vertex.
• Acyclic Graph: An acyclic graph does not contain any cycles.

## Graph Operations

Graphs support various operations that can be performed on them:

• Addition of Vertices and Edges: It is possible to add new vertices and edges to a graph, modifying its structure.
• Removal of Vertices and Edges: Similarly, vertices and edges can be removed from a graph.
• Traversal: Traversal involves visiting all the vertices in a graph, allowing you to analyze or manipulate the data associated with each node.
• Searching: You can search for specific vertices or edges within a graph based on certain criteria.
• Pathfinding: Pathfinding algorithms help find the shortest path between two vertices in a graph.

## Applications of Graphs

The versatility of graphs makes them applicable in various real-world scenarios, including but not limited to:

• Social networks