Graph theory was first introduced in the 18th century by Leonhard Euler to solve a famous problem known as the Königsberg bridge problem, which asks whether it is possible to walk around the Königsberg bridge while crossing over each of the seven bridges exactly once. The bridge looks as follows:
Before we move on, try it out for yourself by using your finger to trace along the path or draw it and trace it with a pencil. Did you manage to find a solution? It's alright if you didn't!
Let's stop for a moment and ask ourselves what exactly a graph is. A graph (G) is a mathematical structure made up of two sets—vertices (V(G)) and edges (E(G)). Two vertices (v1 and v2) are connected if there is an edge (e or (v1, v2)) between them. Now that that's settled, there are some rules associated with graphs...
