Route finding algorithm written in prolog.
Find all routes between station A and station B and sort them by shortest time.

Case study

Berlin Subway (Ubahn)
Mapped lines: U1 -> U9

Use

Install swi prolog
brew install swi-prolog or see here
Launch the REPL in the project folder with swipl

In the REPL

• load the program with [rails]. or ['rails.pl'].
• use predicate route/2
• ; next result, . stop
• exit the repl with halt.

?- [rails].
true.

?- route('Alexanderplatz', 'Mehringdamm').
Alexanderplatz u5 -> Unter den Linden  ❯ Hauptbahnhof (3)
Unter den Linden u6 -> Mehringdamm  ❯ Alt-Mariendorf (4)
14.1 minutes / 4.2 km
true ;
Alexanderplatz u2 -> Stadtmitte  ❯ Ruhleben (5)
Stadtmitte u6 -> Mehringdamm  ❯ Alt-Mariendorf (3)
15.0 minutes / 4.5 km
true ;
Alexanderplatz u8 -> Kottbusser Tor  ❯ Hermannstraße (4)
Kottbusser Tor u3 -> Hallesches Tor  ❯ Krumme Lanke (2)
Hallesches Tor u6 -> Mehringdamm  ❯ Alt-Mariendorf (1)
20.3 minutes / 5.4 km
true

As binary

• compile with swipl --stand_alone=true -o rails -c main.pl
• run with ./rails Alexanderplatz "Kottbusser Tor"
• or with json output ./rails --json Alexanderplatz "Kottbusser Tor"