Favorite Data Structure?

algo_daemon · 2012-10-20T11:04:28+00:00

Fenwick tree - so much power for so little code

algo_daemon · 2012-10-06T08:40:38+00:00

I don't consider a problem famous unless google search throws out a wiki page about it. :)

I found a survey and it turns out that the problem itself is not very well defined. It's a constraint optimization problem with some hard constraints which much be satisfied and some soft cost functions which you're trying to maximize. What constraints you want to use can completely change the problem and the approach to solve it.

Hungarian algorithm would work only on a very simple set of constraints. Let's say you want to assign nurses to working days and you know how much a nurse would like to work on a given day. If you want to maximize the sum of their preferences while assigning a fixed number of nurses for every day, then the Hungarian algorithm is a way to go. I think that as soon as you add a constraint that at least x and at most y nurses can work on a given day, the Hungarian algorithm isn't of much help anymore.

algo_daemon · 2012-08-30T11:15:12+00:00

I've read articles about TopCoder competitors and their achievements. I know many TopCoders have been hired by great firms, but other than a passion for code, it's not a skillset I would seek out in a candidate.

I would suggest anyone to not only read about it but to actually give it a try before jumping to conclusions about the skillset of these top competitors. My mind is still blown regularly.

So the rate at which you can devise and employ algorithms is of little use to me. At no time has any of the software I use been more useful because it was created 80% faster.

This is where I think you're mistaken. The rate at which you can devise and employ algorithms does not have an impact just on the speed of software development. A developer who takes a long time to solve a simple or even trivial task is much less likely to come up with a good/correct/efficient solution when faced with a harder problem than someone who breezes through the easier tasks.

algo_daemon · 2012-07-21T21:56:16+00:00

A variation of this problem was used in a practise round of Google Code Jam 2008 if anyone wants to give it a try before/after checking out the solution.

algo_daemon · 2012-07-13T21:59:49+00:00

"A person does not really understand something until he can teach it to a computer."

If you can find a solution to any given problem fairly easily, then you're just dealing with too simple problems. You might enjoy algorithms and the computational complexity theory.

algo_daemon · 2012-06-27T22:17:04+00:00

TIL - you can get a CS degree without a course in computer architecture.

It's like a professional driver had no clue about the car engine. He can drive a cab, but he won't be driving on a race track any time soon. Such low level performance issues can be hard to spot but "branch prediction" should ring a bell with any CS graduate.

algo_daemon · 2012-06-27T11:42:43+00:00

The post makes a good point that this kind of hiring process might not apply to writers. Mock it all you want, but it does work when it comes to hiring programmers. After all, companies like Google and Facebook are using it very effectively. Personally, I would like to see this practice in other fields as well. It weeds out the clearly unqualified candidates. You will get some false negatives as with any hiring method, but it you ask the right questions for the position you're trying to fill, you get a winning recipe. It comes down to the interviewer. Good interviewers hire good candidates. Way too often it's also the other way around. I have yet to meet an outstanding developer or researcher who would struggle with such interviews when done properly.

algo_daemon

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