What is the difference between a directed graph and an undirected graph?

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What is the difference between a directed graph and an undirected graph?

The main difference between a directed graph and an undirected graph lies in the way the edges are defined and interpreted.

In an undirected graph, the edges do not have any specific direction associated with them. This means that the relationship between two vertices is symmetric, and the edge can be traversed in both directions. In other words, if there is an edge connecting vertex A to vertex B, it implies that there is also an edge connecting vertex B to vertex A. Undirected graphs are often used to represent relationships where the direction of interaction is not significant, such as social networks or friendship graphs.

On the other hand, in a directed graph, also known as a digraph, the edges have a specific direction associated with them. This means that the relationship between two vertices is asymmetric, and the edge can only be traversed in the specified direction. If there is an edge connecting vertex A to vertex B, it does not imply that there is an edge connecting vertex B to vertex A unless explicitly defined. Directed graphs are commonly used to represent relationships where the direction of interaction is important, such as web page links or dependencies between tasks in a project.

To summarize, the key difference between a directed graph and an undirected graph is the presence or absence of a specific direction associated with the edges. Undirected graphs have symmetric relationships, while directed graphs have asymmetric relationships.