What is a Graph? · Graphs

Lesson 2

Nikolai Chukhin · Alexander S. Kulikov

In order to solve this problem, one can draw the following simple picture. First, we draw a circle for every city in the country.

Now, if there is a direct flight between two cities, we connect the corresponding two circles by a line.

It is easy to see now that there is no direct flight between \(A\) and \(D\). However, one can fly from \(A\) to \(D\) with a stop at \(B\) or with a stop at \(C\). There is also a flight with two stops which would go through \(E\) and \(C\).