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Introduction to Graph in Data Structure

Graph in Data Structure: In this article, we are going to see what is graph data structure and types of graphs?
Submitted by Souvik Saha, on March 17, 2019

What you are going to learn?

In this article, we learn about the introduction to Graphs in Data Structure and Algorithm.

• What are the components in Graph?
• Types of the Graphs.
• How we use the Graph data structure?

Graph

The graph is an abstract data type in computer science. It maps the value between two data nodes.

Figure 1.1

Components

1) Node: In the above example, Graph(Figure 1.1) there is a set of nodes. Nodes basically store values of data types ( int, float etc). In the example A, B, C, D, E, F are the nodes of the graph.

2) Edge: In the example graph, there is a set of edges in a graph. Edges make a relationship between two nodes or they are a connection between nodes in a graph. In the example e1 , e2, e3, e5, e6 ,e7,e8are the edges in that graph. Edges can be weighted or unweighted. In the case of a weighted edge, each edge is assigned a weight.

Types

There are two types of graphs,

1) Directed Graph: When all the edges have a direction from one node to another node then the graph is called Directed Graph. (Figure 1.2)

Figure 1.2

2) Undirected Graph: When all the edges have no direction then it called Undirected Graph. The edges start from one node and go to another node. (Figure 1.1)

Real life Application of graphs:

• Building recommendation system for e-commerce websites
• Facebook friend circle
• GPS system Google maps