programming-for-dummies

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Understanding Graphs
An undirected graph
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5
2
6
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Figure 5-3:
The three
types of
graphs.
A directed graph
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A weighted graph
You can also combine weights with direction and create a directed, weighted
graph.
Uses for graphs
Graphs are used to model a variety of real-world problems, such as finding
the most efficient way to route e-mail through a computer network to finding
the shortest way for airplanes to travel to different cities. Molecular biologists
even use graphs to model the structure of molecules.
Designing a single path with the Seven Bridges of Königsberg
One of the first uses for graphs appeared in 1736 in a problem known as the
Seven Bridges of Königsberg. The question was whether it was possible to
walk across all seven bridges of Königsberg exactly once, as shown in
Figure 5-4.