Something I did not know

Post by **thibodeaux** » Mon Nov 22, 2010 7:58 pm

If you have a single-elimination tournament with N (where N is any finite, positive non-zero integer) teams, how many total games will there be?

I knew the answer for values of N that are powers of 2, but I didn't know the general answer. It's just not something that I ever thought about.

Post by **TheCatt** » Mon Nov 22, 2010 9:03 pm

It's like magic.

Post by **thibodeaux** » Mon Nov 22, 2010 9:04 pm

Yeah.

Malcolm · Post by **Malcolm** » Tue Nov 23, 2010 1:15 am

thibodeaux wrote:If you have a single-elimination tournament with N (where N is any finite, positive non-zero integer) teams, how many total games will there be?

I knew the answer for values of N that are powers of 2, but I didn't know the general answer. It's just not something that I ever thought about.

In general, n isn't a power of 2, people cheat the value to make it so using bye weeks or wildcard teams.

Post by **thibodeaux** » Tue Nov 23, 2010 7:51 am

Yeah, but it doesn't matter; you can do it without a power of 2.

Post by **TheCatt** » Tue Nov 23, 2010 9:28 am

Malcolm wrote:
thibodeaux wrote:If you have a single-elimination tournament with N (where N is any finite, positive non-zero integer) teams, how many total games will there be?

I knew the answer for values of N that are powers of 2, but I didn't know the general answer. It's just not something that I ever thought about.
In general, n isn't a power of 2, people cheat the value to make it so using bye weeks or wildcard teams.

It's not a cheat. It's just a fact.

Malcolm · Post by **Malcolm** » Tue Nov 23, 2010 10:47 am

thibodeaux wrote:Yeah, but it doesn't matter; you can do it without a power of 2.

Did you find/derive the general answer? I'm slightly curious.

Post by **TheCatt** » Tue Nov 23, 2010 10:57 am

Ummm...

Post by **thibodeaux** » Tue Nov 23, 2010 11:17 am

Malcolm wrote:
thibodeaux wrote:Yeah, but it doesn't matter; you can do it without a power of 2.
Did you find/derive the general answer? I'm slightly curious.

Yep. If you have N teams, then you need N-1 games.

You can confirm this by thinking of a tournament bracket as a binary tree. You have N leaf nodes (the teams). The games are the internal nodes. Consult wikipedia for the relationship between these two entities.

Post by **thibodeaux** » Wed Nov 24, 2010 7:01 pm

The reason I mention this is that on Monday, and then again today, I interviewed a database-engineer who did not know the answer, not even for powers of 2.

Today's guy actually did try to work through for 64 teams, and he wrote down and added up the powers of 2 from 1 to 32. While he was adding, I said to him, "you know, in binary that's all ones." Didn't help him.

Malcolm · Post by **Malcolm** » Wed Nov 24, 2010 7:26 pm

One of our contractors is getting let go because his SQL skills suck balls. Granted, he wasn't hired for that, he kind of got screwed into a bad position. But, come on, SQL is fucking rocket science. Dude didn't know what the "bit" data type was.

I'm not looking forward to hiring any new members for our team because our hiring process is shyte. Management seems to have solved this problem just by letting manpower dwindle and refusing to hire anyone new.

Edited By Malcolm on 1290644863

Post by **thibodeaux** » Wed Nov 24, 2010 7:41 pm

Malcolm wrote:Management seems to have solved this problem just by letting manpower dwindle and refusing to hire anyone new.

Sometimes you're actually better off that way. Everybody's busy, but at least you know they're competent (I mean, assuming it's the competent ones who are left).

Malcolm · Post by **Malcolm** » Wed Nov 24, 2010 8:11 pm

It's going to be a loooooooooooooooooong while before the real problem idiots are removed.

Post by **TheCatt** » Wed Nov 24, 2010 9:13 pm

The other day, I was talking with one of my fellow DB people at work, and asked him what he thought datalength(13) was in t-sql... He said "2"

Maybe he uses 3 bits to a byte.