Urinal protocol vulnerability | Hacker News Reader

Urinal protocol vulnerability

blag.xkcd.com

50 pointsKototama15 comments

His objective function is wrong, I think: it considers only the total number of people we can accommodate with all spacings >= 2, but if that were the only thing people cared about then we wouldn't have the "use the middle of the biggest gap" algorithm in the first place. And apparently no one ever finishes.

The model would be appropriate for the following situation: people turn up sequentially but rapidly; once someone starts peeing they stay where they are for ever; anyone who arrives and is unable to find a urinal whose neighbours are unused immediately commits suicide out of embarrassment.

See also: Chinese Restaurant Process lying about an infinite number of available tables, Indian Buffet Process lying about an infinite number of available dishes, Dining Philosophers not being smart enough to go get another pair of chopsticks, etc.

Mathematicians are dumb.

Yeah, but his model has an exact solution. It's a nice mathematical problem even if it doesn't reflect actual urinal behavior.

But... in even the 'best' situations, half the urinals are going unused! I wonder if putting up a small wall between each urinal would be a good idea?

Most urinals in India have these - a small wall-ish slab between urinals that start from about knee-height and end at about chest-height.

These are going the way of the dodo now though, for whatever inexplicable reason. (Cost, maybe?)

Lots of places (in the US) have this, but it's ineffective to prevent Awkwardness - they only cover the height of the urinal itself. To fully prevent Awkwardness, I think you need full-height walls, so you can't see your fellow visitor's face.

Or even...cubicles!

They're called stalls

I don't know about you guys but when I go to bathroom and its empty i always take the middle place first. You can learn more about the complicated rules here http://www.albinoblacksheep.com/flash/urinal . It has other interesting advices like if you have to pee close to somebody make sure he is not huge bodybuilder :)

How does this work at Wrigley Field?

(for those who don't know, it's a baseball park in Chicago; the men's restrooms have one large "trough" style urinal along the whole length of the wall)

That's ultimate awkwardness, regardless of the number of men using it.

They're also highly inefficient. I've been to a ball game (not in Wrigley Field, but with similar troughs) where only 2 guys, on extreme ends, were using the trough. A dozen guys were waiting in line for stalls or the trough corners to be vacated.

What's worse, there are sinks at the end of the troughs at Wrigley that shower water down, and every once in a while some drunk guy can't tell the difference....

When you mix it up with sports its not awkward any more.

Am I the only one that doesn't care if somebody sees my dick?

I also don't care if somebody sees your dick.

Reply on news.ycombinator.com