Desktop challenge!

Beary · Post by **Beary** » 02 Jul 2006, 09:56

I have 110 in my fist attempt, starting at Epping finishing at Amersham.

Root · Post by **Root** » 02 Jul 2006, 10:00

I assume you're not allowed to use the North Curve, else you could have Croxley added to that.

hwolge · Post by **hwolge** » 02 Jul 2006, 15:15

128 is the number!

I couldn't help myself - I just had to find out the ultimate solution.

My program says 128 (Epping - H&W), a route I verified manually is a correct one. I believe the route is unique, except for the minor variations of Farringdon/Barbican vs Old Street/Angel and, of course, reverse order.

There are 127-routes finishing at Heathrow, which means that T4 will allow more 128-routes with Heathrow finish!

tpfkar · Post by **tpfkar** » 02 Jul 2006, 17:04

Just to add flavour, when i posted before I had I think 121, Epping to Upminster!

Will try to work out the 128.

gasman · Post by **gasman** » 02 Jul 2006, 18:22

Ah good, I was just on the verge of writing a program myself, and now I don't have to... mind you, I couldn't think of any elegant algorithm for it, so it could have taken quite a while to do a brute-force search of all possible routes.

Once people have finished looking for the solution, I quite like the idea of drawing a map of the 128 route by deleting all the unused bits of track from the tube map. Could be quite pretty, I think.

hwolge · Post by **hwolge** » 02 Jul 2006, 19:15

I'd say there is no elegant algorithm. Brute force JUST managed this time (some manual ad hoc limitations set though...). It took maybe 30 minutes to exhaust the Epping start. (I double checked by starting at H&W at it came up with the same solution.

gasman · Post by **gasman** » 02 Jul 2006, 21:47

Armed with your hints I've now worked out a 127 (Epping-H&W) by hand. I'm sure I'm overlooking something obvious, because that route misses out Piccadilly Circus and Charing Cross...

tpfkar · Post by **tpfkar** » 03 Jul 2006, 01:20

I've been up late tonight trying to find the 128 route by hand, and I've finally got something good, counted it up and made....129!!

Cue controversy!
I've triple checked the addition, and I'm pretty sure it's valid. No double stations or non-LU connections.

Am I ********?

hwolge · Post by **hwolge** » 03 Jul 2006, 06:58

129 is the number!

No, you're not (********) - I'd never suggest that!

Forget everything you may have read in this post earlier today - it's been totally edited!

The explanation for the 128/129 discrepancy is simple (and slightly embarrasing for me) - I used (old) data without Queensway stops! My route does however pass through Queensway, so I'm now convinced we have the same (and only) perfect solution!

Well done tpfkar!

hwolge · Post by **hwolge** » 03 Jul 2006, 17:37

And here they are:
Epping-Theydon Bois-Debden-Loughton-Buckhurst Hill-Woodford
Woodford-Roding Valley-Chigwell-Grange Hill-Hainault-Fairlop-Barkingside-Newbury Park-Gants Hill-Redbridge-Wanstead-Leytonstone-Leyton-Stratford-Mile End
Mile End-Bow Road-Bromley-by-Bow-West Ham
West Ham-Canning Town-North Greenwich-Canary Wharf-Canada Water
Canada Water-Rotherhithe-Wapping-Shadwell-Whitechapel
Whitechapel-Aldgate East-Liverpool Street
Liverpool Street-Aldgate-Tower Hill-Monument-Cannon Street-Mansion House-Blackfriars-Temple-Embankment-Westminster
Westminster-Waterloo-Southwark-London Bridge
London Bridge-Borough-Elephant & Castle-Kennington-Oval-Stockwell
Stockwell-Vauxhall-Pimlico-Victoria
Victoria-Sloane Square-South Kensington
South Kensington-Knightsbridge-Hyde Park Corner-Green Park-Piccadilly Circus
Piccadilly Circus-Charing Cross
Charing Cross-Leicester Square
Leicester Square-Covent Garden-Holborn
Holborn-Chancery Lane-St. PaulÃ‚Â´s-Bank
Bank-Moorgate-Old Street-Angel-KingÃ‚Â´s Cross St. Pancras-Euston
Euston-Warren Street-Goodge Street-Tottenham Court Road
Tottenham Court Road-Oxford Circus-Bond Street-Marble Arch-Lancaster Gate-Queensway-Notting Hill Gate
Notting Hill Gate-High Street Kensington-Gloucester Road
Gloucester Road-EarlÃ‚Â´s Court-West Kensington-Barons Court-Hammersmith (District)-Ravenscourt Park-Stamford Brook-Turnham Green-Chiswick Park-Acton Town
Acton Town-Ealing Common-North Ealing-Park Royal-Alperton-Sudbury Town-Sudbury Hill-South Harrow-Rayners Lane
Rayners Lane-West Harrow-Harrow-on-the-Hill-Northwick Park-Preston Road-Wembley Park
Wembley Park-Neasden-Dollis Hill-Willesden Green-Kilburn-West Hampstead-Finchley Road-Swiss Cottage-St. JohnÃ‚Â´s Wood-Baker Street
Baker Street-Marylebone-Edgware Road (Bakerloo)-Paddington-Warwick Avenue-Maida Vale-Kilburn Park-QueenÃ‚Â´s Park-Kensal Green-Willesden Junction-Harlesden-Stonebridge Park-Wembley Central-North Wembley-South Kenton-Kenton-Harrow & Wealdstone

gasman · Post by **gasman** » 04 Jul 2006, 21:23

As vaguely promised, the route map.

Took me bloody ages, it did.

Sillert, V.I. · Post by **Sillert, V.I.** » 04 Jul 2006, 22:32

Ok so now who's gonna go out there & set a time for it.

Alternatively, (and in keeping with the spirit of the desktop challenge theme) what's the shortest time you can get using journeyplanner?

(allowing a reasonable minimum time for the changes)

tpfkar · Post by **tpfkar** » 05 Jul 2006, 08:08

Yes, that's the exact route I had. Bit of a fluke if it's unique.

As soon as I tried linking Baker St to Paddington on the Bakerloo, the rest fell into place.

Nice challenge - got any more?

Post by **tubeguru** » 05 Jul 2006, 09:16

I reckon one of you needs to go out and get a time for that route so we can see just how long it takes.

Going Underground · Post by **Going Underground** » 05 Jul 2006, 09:21

tubeguru wrote:I reckon one of you needs to go out and get a time for that route so we can see just how long it takes.

Sounds like a good idea, also we need a name for this route/challenge

tubechallenge.com

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