UK24727: a shortest-possible walking tour through the pubs of the United Kingdom | Hacker News Reader

UK24727: a shortest-possible walking tour through the pubs of the United Kingdom

math.uwaterloo.ca

83 pointsrobinhouston21 comments

Based on alcohol metabolism rate, how long would the pub crawl take (ignoring liver failure)? What's the optimal rate of inebriaton - equal intervals or concentrated intakes. We need an equally dedicated team of doctors to get on this.

As steady as possible. Your liver processes alcohol continuously, so you want to hit your optimal BAC by drinking somewhat faster at first and then maintaining it.

Looks like the whole folder has been deleted. Does anyone have a copy?

https://webcache.googleusercontent.com/search?q=cache:FNC1ma...

This is something I've been meaning to put together a post on, where NP problems are actually easy to solve. Take the subset sum search problem as an example, there's 2 "regions" of the problem space where total solutions can be done in P. If the values are either relatively small or relatively large, solving it is quite easy:

Find 23 given [1, 2, 2, 3, 1...] Find 40 given [35, 15, 98, ...]

A lot of situations where you might give up on trying to compute an exact solution can turn out to have underlying data that makes it possible.

This is very cool, though I was intrigued nowhere in the central Highlands is covered (or the entire Isle of Skye, which is accessible by pedestrians from the mainland) as there are many pubs there, including those listed on the Pubs Galore site used as the dataset, such as http://www.pubsgalore.co.uk/pubs/51660/ (or, say, the four listed in Mallaig, also not reached on the route at all).

I wouldn't want to walk the A830! But yes, it is surprising. My immediate reaction in Skye's case was that it would be because Google Maps only suggests the route via the ferry, but I noticed those are included to the Isle of Man, so who knows what the deal is there.

Edit: also, if you are gonna go to Eriskay you might as well take the ferry to Barra and go to the Castlebay Bar to watch the Vatersay Boys ;)

From the data description:

For our data set, we pruned the full list. First, based on names, we removed establishments that seemed more like restaurants than public houses. So TGI Friday's was out and the The Plough and Horses was in. Second, we took only the first location of pubs that had a number of branches in the same town. Third, we removed any pub that was marked as permanently closed by the members of Pubs Galore. Finally, we removed several pubs that could not be reached by foot, such as those located in airport terminals.

The little loop near Columbia Road in the very upper-right of this pic is a bit odd: http://www.math.uwaterloo.ca/tsp/pubs/img/london_zoom.jpg

It's taking two separate paths to get from the pub in the bottom-left of the loop to the intersection that creates the loop. One of these paths must be shorter, so why isn't that path taken both to and from that pub?

They may be using a public transit route which goes in only one direction or can only be boarded at the point on the other side of the loop.

"a shortest-possible walking tour"...

"You see that we obviously cannot walk several of the indicated routes"

The solution does not use public transport. Also, checking Google Maps shows that the roads are not one-way. This suggests that the claims of the authors that this is an optimal solution is incorrect.

So it turns out that for all the pubs currently listed in the UK, the shortest path is 28,269 miles. That's actually pretty doable: were one independently wealthy and heavily beer-minded, one could do it in 10-15 years of hard (and thirsty) work!

Many pubs in Scotland are missing, not only on the islands but also on the mainland. Nairn, Forres and Applecross all appear without pubs on the map, but it is easy to check Google to see that all of these towns have pubs.

Likewise for the Isle of Man.

Pedantic comment: the Isle of Man isn't in the United Kingdom.

Well, they did say that they restricted themselves to the 24k pubs in the Pubs Galore guide.

Pubs Galore shows pubs in Nairn, Forres and Applecross.

http://www.pubsgalore.co.uk/towns/nairn/highland/ http://www.pubsgalore.co.uk/towns/forres/grampian/ http://www.pubsgalore.co.uk/pubreviews/51349/

EDIT: maybe these were added after they snapshotted the data.

This comment kind of misses the whole point.

As both a pub-loving UK citizen and someone who has just finished the excellent book 'In Pursuit of the Travelling Salesman' (written I think by the authors of this article), this is a highly timely submission!

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