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# Shortest path between two subway stations in Paris!?

## Shortest path between two subway stations in Paris!?

(OP)
Hi,

I am quite new to PROLOG and I need to write this program, but I have no ideas. I would be very grateful for any help!

Assignment:
Write predicates in PROLOG to solve the folowing problem:

"To find the shortest path between two subway stations in Paris."

Here is the text file (nodes.txt), where his contents is:
* stationFrom - name of the station from where it starts;
* lineFrom - number of metro line from where it starts;
* stationTo - name of the station to where it will arrived;
* lineTo - number of metro line to where it will arrived;

The specified file should be used to generate facts based on
knowledge. There should be a predicate:

solve(StartStation,EndStation,Path).

Who within the arguments StartStation and EndStation are input and refer to the names of the initial and final station respectively, while Path argument is an output argument and a list of names stations that need to pass to get from home to the final station (in shortest way).

Note: The distances between any two stations that have direct connections are equal.

### RE: Shortest path between two subway stations in Paris!?

So you should really combine a path-search algorithm that will return a list of nodes with the 'length' predicate that computes the length of a list and voila: you have an algorithm that computes paths.

Path-search algorithms are a very common topic here, if you do a manual search in the last 30 topics, you'll find at least two threads referring to path-searching. You should adapt them to your particular needs described in the file you attached

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