Let's start with the question what is a graph? Broadly speaking, a graph is a data structure that consists of nodes (also called vertices) and edges. Each edge connects two nodes. A graph data structure does not require any specific rules regarding connections between nodes, as shown in the following diagram:
The afore mentioned concept seems very simple, doesn't it? Let's try to analyze the preceding graph to eliminate any doubts. It contains nine nodes with numbers between 1 and 9 as values. Such nodes are connected by 11 edges, such as between nodes 2 and 4. Moreover, a graph can contain cycles, for example, with nodes ...
