- see if it is possible to take every possible flight route exactly once and end up at the original airport where we started the trip
- find shortest path from city A to city B
- find a city that has the most amount of connecting cities
- Find out if the graph is Eurolian or not.
- BFS search.
- Calculate maximum degree of the graph.
sample data from https://github.com/krlawrence/graph/tree/master/sample-data