Algorithms For Dummies

 Exploring the World of Graphs

You do things like count the edges and vertexes to determine things like graph 

complexity. Seeing a graph also enables you to perform tasks like computing cen-

trality with greater ease. Of course, you build on what you discover in this chapter 

in Chapter 9.

The numeric presentation of a graph is important, even if it makes understanding 

the graph hard. The plot is for you, but the computer doesn’t really understand the 

plot (despite having drawn it for you). Think of the computer as more of an 

abstract thinker. With the need to present a graph in a form that the computer can 

understand in mind, this chapter discusses three techniques for putting a graph 

into numeric format: matrixes, sparse representations, and lists. All these tech-

niques have advantages and disadvantages, and you use them in specific ways in 

future chapters (beginning with Chapter 9). Other ways are also available to put a 

graph in numeric format, but these three methods will serve you well in commu-

nicating with the computer.