What Are the Two Primary Types of Graphs in Data Structure?

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Larry Thompson

What Are the Two Primary Types of Graphs in Data Structure?

Graphs are an essential data structure used in computer science to represent relationships between different objects. They are composed of vertices or nodes, which are connected by edges. There are various types of graphs, but the two primary types are directed graphs and undirected graphs.

Directed Graphs

A directed graph, also known as a digraph, is a graph in which edges have a specific direction. This means that the relationship between vertices is one-way. Each edge has an origin vertex and a destination vertex.

To visualize a directed graph, you can think of it as a network of roads with one-way traffic. Each road connects two locations, and you can only travel in the direction specified by the road.

In HTML, we can use an unordered list (

    ) to represent the vertices and their connections using list items (

  • ). We can apply some styling to enhance readability:

    <ul>
      <li>Vertex A
        <ul>
          <li>Vertex B</li>
          <li>Vertex C</li>
        </ul>
      </li>
      <li>Vertex B
        <ul>
          <li>Vertex D</li>
        </ul>
      </li>
      <li>Vertex C
        <ul>
          <li>Vertex D</li>
        </ul>
      </li>
      <li>Vertex D</li>
    </ul>
    

    This representation shows that Vertex A is connected to Vertex B and Vertex C, while Vertex B is connected to Vertex D. Similarly, Vertex C is connected to Vertex D.

    Undirected Graphs

    Unlike directed graphs, undirected graphs do not have a specific direction assigned to their edges. The relationships between vertices are bidirectional, meaning you can travel in any direction between two connected vertices.

    To visualize an undirected graph, imagine a network of roads where traffic can flow in both directions. You can move freely between any two locations using the available roads.

    In HTML, we can again use an unordered list (

      ) to represent the vertices and their connections using list items (

    • ):

      <ul>
        <li>Vertex A
          <ul>
            <li>Vertex B</li>
            <li>Vertex C</li>
          </ul>
        </li>
        <li>Vertex B
          <ul>
            <li>Vertex A</li>
            <li>Vertex D</li>
          </ul>
        </li>
        <li>Vertex C
          <ul>
            <h3>Subheading: List of Connections of C</h3>
                     List Item: Vertex A
                     List Item: Vertex D
          </ul>
        </li>
        <li>Vertex D
          <ul>
            <li>Vertex B</li>
            <li>Vertex C</li>
          </ul>
        </li>
      </ul>
      

      This representation shows that Vertex A is connected to Vertex B and Vertex C, while Vertex B is connected to Vertex A and Vertex D. Similarly, Vertex C is connected to Vertex A and Vertex D. Lastly, Vertex D is connected to both Vertex B and Vertex C.

      Understanding the differences between directed graphs and undirected graphs is crucial for various algorithms and applications in computer science. By utilizing proper HTML styling elements like bold, underline,

        unordered lists

      , and

    • list items
    • , we can make our content visually engaging and organized.

      So, whether you are working on a project that involves representing relationships or exploring graph algorithms, having a solid understanding of these two primary types of graphs will undoubtedly be beneficial.