Need to hire someone

[aussielong]

I think the problem is finding a best fit in a second tree, for each node walked in the first tree

I think you missed the point. Reread the question.

[d000hg]

Without knowing the rate you are willing to pay it is not possible to say whether this is a good question.

It doesn't matter how little you are paying, if they can't asnwer a simple question like this they aren't much use.

[fullyautomatix]

It's a fairly small co, rate would be ~ £500/day for the right person. Which wouldn't be you with an attitude like that. We need a competent programmer who knows java well and a few other common bits and bobs. TBH, most programmers aren't competent, it's like trying to hire a mechanic when most of them only do clutches and have never seen brakes.

Anyway, you're rather missing the point of the post, which is what's the best way to find someone? If you can give intelligent feedback on what sort of interview questions to ask rather than ranting like a spoiled dickwad who's just been told he can't recode the whole thing in python that would be helpful.

For 500 PD rate you want someone who can come up with some tree processing logic on the spot and list all the GOF patterns. I bet you also want him to polish your shoes everyday.

The worst mistake to make in an interview is asking for a solution to a problem and expecting a particular answer. Everybody solves problems in their own way and its very rare to find someone answering a generic question in a specific way. You can spot a good programmer by just discussing a problem and techniques to solve it.

[DimPrawn]

For 500 PD rate you want someone who can come up with some tree processing logic on the spot and list all the GOF patterns. I bet you also want him to polish your shoes everyday.

The worst mistake to make in an interview is asking for a solution to a problem and expecting a particular answer. Everybody solves problems in their own way and its very rare to find someone answering a generic question in a specific way. You can spot a good programmer by just discussing a problem and techniques to solve it.

Yes, a better line of questioning is something like:

We have alot of data in our business represented by tree like structures.

Have you dealt with data like this before?
If so, how was it represented and processed?
What are the ways of storing and querying tree data?
What are the ways of traversing and copying data in tree structures?
What are the trade-offs in speed and data storage for various implementations you can think of?
How might you represent a tree structure in a database, object model and flat file?
What if only leaf nodes be represented , how might you optimise the data structure in this case?

[fullyautomatix]

Yes, a better line of questioning is something like:

We have alot of data in our business represented by tree like structures.

Have you dealt with data like this before?
If so, how was it represented and processed?
What are the ways of storing and querying tree data?
What are the ways of traversing and copying data in tree structures?
What are the trade-offs in speed and data storage for various implementations you can think of?
How might you represent a tree structure in a database, object model and flat file?
What if only leaf nodes be represented , how might you optimise the data structure in this case?

Good stuff. I think Doobad has enough now to find someone suitable. Despite this if he cannot find anyone taking his job I bet its because of his smelly socks.

[DimPrawn]

The key point in interview questions is they should start off easy like "have you done this before yes/no?" then move on to talk about how you did x and y, then throw in some harder to answer ones like compare and contrast this implementation and how might you implement it given these constraints and requirements.

[doodab]

Are you guys seriously telling me that you'd give a Java dev who couldn't come up with a method for walking a tree and didn't know a decorator from a builder £500 / day?

For 500 PD rate you want someone who can come up with some tree processing logic on the spot and list all the GOF patterns. I bet you also want him to polish your shoes everyday.

No, I want someone has some idea of where / how to start trying to solve the problem. It isn't a complicated problem.

The worst mistake to make in an interview is asking for a solution to a problem and expecting a particular answer. Everybody solves problems in their own way and its very rare to find someone answering a generic question in a specific way. You can spot a good programmer by just discussing a problem and techniques to solve it.

This is exactly the point of the question.

I'm looking for some intelligent questions and a high level answer with extra points for namedropping a couple of GoF patterns. Is that too much to ask?

The use of patterns when describing the answer is a bonus. More importantly the absence of them shows that someone is either not experienced enough to have come across them or hasn't bothered to learn about something that comes up a lot in their chosen field. Whomever we hire is going to have a learning curve of some description, so evidence of proactive learning is a good thing.

It also means that we would share a common vocabulary that would make understanding the existing codebase + various 3rd party stuff we use + explaining new ideas easier.

[aussielong]

The key point in interview questions is they should start off easy like "have you done this before yes/no?" then move on to talk about how you did x and y, then throw in some harder to answer ones like compare and contrast this implementation and how might you implement it given these constraints and requirements.

That's a good approach.

I go through their CV in the interview and ask them questions about anything that interests me. This usually starts a line of questioning that opens up more depth and I can gauge their level of involvement in the piece.

I get them to draw a design on the board- something they worked hard on.

Then I go through business knowledge questions, if they claim to have business knowledge.

Then questions specific to the platform we work on.

Then I ask them how they would approach solving a typical problem we come across day to day on our systems.

They have to do a programming test to get this far so I don't bother with that. I do ask a few algorithms questions though.

[EternalOptimist]

devs may be dunces. but a typical interview question might as well be

'We have a requirement. Along the way you will meet unspecified hurdles, in unknown areas. You will have an unknown amount of time to crack each problem, with unknown support, and the known spec that we gave you will be superceded at least once a week and is therefore an ongoing unknown'

now, you are obviously thicker than I am, and a dunce, but do you think you can do it ? by the way the coffee is not free

[DimPrawn]

devs may be dunces. but a typical interview question might as well be

'We have a requirement. Along the way you will meet unspecified hurdles, in unknown areas. You will have an unknown amount of time to crack each problem, with unknown support, and the known spec that we gave you will be superceded at least once a week and is therefore an ongoing unknown'

now, you are obviously thicker than I am, and a dunce, but do you think you can do it ? by the way the coffee is not free

You are sasguru and I claim my free ecoshed.