Depth First Traversal of Graph

What is a Graph?

Graphs represent pairwise relationships between objects. Graphs are mathematical structures and therefore can be visualized by using two basic components, nodes and edges

A node, also known as a vertex, is a fundamental part of a graph. It is the entity that has a name, known as the key, and other information related to that entity. A relationship between nodes is expressed using edges. An edge between two nodes expresses a one-way or two-way relationship between the nodes.

Graphs can be represented as Adjacency Matrix or Adjacency List. We will be using adjacency list representation for this course. If you want to study graphs in detail, review Interview Refresher Course on Data Structures in Python.

The diagram below shows an example graph. It had $6$ nodes and $6$ edges.