Journey Planner Challenge – You need to visit 5 tube stations | Hacker News Reader

Journey Planner Challenge – You need to visit 5 tube stations

edjefferson.com

29 pointscronyn31 comments

I take it you need to live in London for this? Else I don't understand how I'm supposed to figure it out?

Yeah - to me it seems pretty much to rely on how well you've memorized the TFL network, and London's geography as a whole.

As someone that works, but doesn't live in London, I found this mildly fun, but can definitely appreciate that it would be near impossible for someone that doesn't visit frequently.

edit: It would also be nice to know some of the technical implementation details - Is the TFL journey planner data exposed via an API?

And also whether it's a familiar stomping ground - I got full marks on the first one (though not without a bit of thought) as it was right around where I went to university; next one I didn't have a clue.

> Is the TFL journey planner data exposed via an API?

Sure is, complete with swagger UI. https://api.tfl.gov.uk/

Most of their endpoints seem to be rate limited only if uncached in the CDN.

That means you can write bots as long as the bots stay mostly on cached stuff. You can tell if something was cached, because you get a response in tens of milliseconds rather than hundreds of milliseconds.

I've been polling some of their pages every second for many years now without issues since learning that.

There may be some more official way...

> Yeah - to me it seems pretty much to rely on how well you've memorized the TFL network, and London's geography as a whole.

Having had a (very quick) look at a few of the challenges, this appears to be a Zone 1 and 2 based challenge.

A true Londoner would never stoop so low as to need to refer to a printed map of Zones 1 and 2. Any Londoner worth their salt should be able to give you an immediate un-referenced answer as to how to get between two points in Zones 1 and 2.

Beyond zone two, other than the obvious (POIs, airports, terminal stations etc.) then most Londoners would likely need to refer to a map !

EDIT:

The implementation seems to have a few bugs, for example, proposed "solution":

Stamford Brook - West Brompton - Notting Hill Gate - Bermondsey - Stratford

Appears to be rather curious for more than one reason...

There's levels to it though, just had a Burnt Oak / Cockfosters route.

I can't think of a better solution for those five stations. What's the bug?

> I can't think of a better solution for those five stations. What's the bug?

Let's start with the obvious:

"Notting Hill Gate - Bermondsey - Stratford"

Bermondsey[1] is only on the Jubilee Notting Hill Gate[2] is not served by the Jubilee, but Central and Circle/District Stratford[3] is on both Jubilee and Central Line

Therefore try as you might, you are not going to find a train that goes from Notting Hill to Bermondsey and nor is there a direct connection between lines available.

The challenge asks for a "route that passes through all stops". Therefore (I assume) we are only allowing either no connections or direct connections, and not indirect circuitous routes with multiple indirect connections.

After all, most sensible Londoners plan their route that way and would rather, for example, walk, than take a circuitous indirect connection (because walking is often quicker than multiple connections, especially in the central zones).

The other bug:

"Stamford Brook - West Brompton - Notting Hill Gate"

Is just an odd route since Stamford Brook and West Brompton are on different branches, so the answer requires un-necessary tromboning, and in reality there's no sensible answer, because you could equally go "West Brompton - Stamford Brook - Notting Hill Gate", since there's no escaping the Earls Court trombone. Whichever way, it's not a route any sane human would ever take.

[1] https://tfl.gov.uk/tube/stop/940GZZLUBMY/bermondsey-undergro... [2] https://tfl.gov.uk/hub/stop/940GZZLUNHG/notting-hill-gate-un... [3] https://tfl.gov.uk/tube/stop/940GZZLUSTD/stratford-undergrou...

So any Londoner worth their salt should possess the Knowledge, then?

https://www.nytimes.com/2014/11/10/t-magazine/london-taxi-te...

Paging Geoff Marshall...!

He will eventually propose solutions where you exit trains and walk a short distance to get to an other line, instead of following the TfL map.

Well that’s what you’d normally do, struggled with a couple as I tried to work out what it felt was “fastest” where you’d clearly take a bus rather than backtrack to zone 1.

I think it assumes you have to exit and reenter each time rather than just pass through the platform too

Get a PDF copy of the tube map and have a stare at it, then graduate to doing it without the map.

https://tfl.gov.uk/maps/track/tube

Intermediate mode: make yourself a black and white copy of the map by printing it out.

I assumed it had something to do with the color and tried to find patterns. Turns out you need knowledge of the London Metro system. It would be nice if the title reflected that.

Well, the title says "tube", which would be enough of a hint for most people, I think.

Please define "most people".

People who know that in london the subway is called the tube.

Well, I suppose my sample is mostly "public transport nerds", which may not be representative.

“ As an AI text model, I am unable to visually plot routes on a map. However, I can provide you with a suggested route to travel through all five stops in the fastest manner possible, assuming you're using the London Underground.

Start at Southwark station (Jubilee Line). Take the Jubilee Line towards Stanmore and get off at London Bridge station (1 stop). Continue on the Jubilee Line towards Stanmore and get off at Green Park station (4 stops). Change to the Victoria Line at Green Park station. Take the Victoria Line towards Brixton and get off at Westminster station (2 stops). Change to the Jubilee Line at Westminster station. Take the Jubilee Line towards Stanmore and get off at Bond Street station (2 stops). Please note that this suggested route is based on the information available up until 2021 and is subject to change due to any updates or closures on the London Underground network. For the most accurate and up-to-date information, please use Transport for London's journey planner or a real-time map application.”

Was this correct?

Sadly, it's mostly nonsense. It first tells you to travel in the wrong direction, then go back on yourself, then take a route that doesn't exist (Green Park to Westminster on Victoria, in 2 stops, when it would only take 1 on the Jubilee)...

Somewhat relieving, if it was accurate I was going to say it was probably the most impressive GPT result I've seen so far.

Reads like it might be nearly ready to play Mornington Crescent, though.

Unfortunately AI was banned (in tournament play, anyway) in the year 1641.

Not, however, if the Duke of Gloucester Variant is in play, which is popular in the shires. Though, naturally, standard Sudbury-type openings are discouraged in that case, unless one is trying for a Wembley Roundabout.

That's true, I forgot because I've never played a lot of DoG myself, since I was raised in the Eastern Dialectic school of thought and never cared much for artichokes anyway.

It told me I did five levels in five attempts but it was more than that.

Similar, not mine: https://metrodle.com

So it's a boring version of Mornington Crescent?

Full marks first attempt up to level 5... Just sayin'

This is super cool!

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