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Blazecock Pileon — Fri, 30 Oct 2009 13:31:34 -0800

Is there an enumeration of complete chess games? Has anyone made an accurate (ideally, "closed form") count of possible chess games?

I found an older article via Google that does a very rough guess-timate of how many complete chess games are possible.

I'm curious if anyone has since tried to count all possible games, given standard FIDE rules, played to completion. Presumably, for example, it is not exponential because some moves will result in an end state ("checkmate" or "stalemate") faster than other moves.

Please do not offer speculation about the answer
Please do not link to Google search results (unless you have found something that answers the question as specifically framed)
Thanks!

Difference between a bag and a purse?

TheOnlyCoolTim — Sat, 24 May 2008 20:06:36 -0800

What is the difference between a purse and a bag? It is 11 PM on Friday and I need to know this. My friend has a bag which I say is a purse. When I saw it I thought at first it was some girl's purse. Men can carry purses, and purses are subsets of bags, but let's have a logical definition.

My theory is that a purse is accessed while being carried/worn, while backpacks and messenger bags, for example, are generally removed before opening.

SQL Combinations

whoojemaflip — Wed, 15 Aug 2007 03:38:28 -0800

Any SQL / math ninja's on the green fancy a quick challenge..? So I've got this table containing number pairs, right, and I need to compute all the possible combinations. For example: I have the following pairs: {1,2}, {1,3}, {3,4}, {2,5}

The implementation I need will produce the following combinations: {1,2}, {1,3}, {3,4}, {2, 5}, {1,3,4}, {1,2,3}, {1,2,5}, {1,2,3,5}, {1,2,3,4}, {1,2,3,4,5}

But not these: {1,4}, {1,5}, {3,5}, {1,2,4}, {1,3,5}

I know, I know, sounds like homework filter but I can assure you it's not - I'm building a shopping cart app thing on LAMP and I can't quite see a clear way around this conundrum. I mean, it could be done recursively in PHP but thats going to involve a) lots of connections / queries to the database, and b) the kind of headaches that only recursion can induce.

Can you see a way of doing this in SQL? Or even an algo which won't hammer the DB server with zillions of l'il queries?