Interview Technical Test Preparation

[jwalters]

Ok, I'm nowhere near the interview phase yet but I am curious: What is the make-up of a technical test? What kind of questions/exercises are to be expected? Should I expect to write code for a specific API or solve math problems with pencil and paper?

I initially read about the technical interview component in JFL's GCG interview and would like to be prepared when the time comes. I managed fine in college but math is not my forte, so I wonder if I should be honing specific skills (e.g. to work out vector/matrix problems for an interview exam).

Can anyone share personal experience on the topic? Are there any sample technical tests available anywhere (though I'm not sure of legal ramifications if they were posted online)? Note that I have read the free GCG mag guide to a game job interview (page 31) which is a great read but only briefly touched on the subject.

Thanks for your thoughts!

[yaustar]

Here is an example of one: http://www.pixietouch.com/blog/?p=47

These will differ from company to company. Some with give you a framework and be asked to make Space Invaders, some paper tests can be plain evil (asking questions on C and ASM), some will be white/black board tests, etc.

[jwalters]

Thanks for the link, yaustar! Fortunately the book I'm learning from right now has a good intro to vector and matrix math in the beginning so I hope I'll be good to go. And I'll try that test on the link you posted soon.

Just curious, what was your technical test like? Do you remember any of the questions or particular ones that stumped you? Did you get them all correct?

I know some more of our friends here have game jobs... let us know about your interview experiences!

[yaustar]

Just curious, what was your technical test like?

I had a quite a large range of tests. Some were relatively straight forward while some were plain evil (who uses C and ASM anymore on a a day to day basis?). To be honest, the tests is just there to check if you can program at a certain level. Think of it as a culling test before seeing any staff.

The actual technical interview is what decides if you get the job or not.

Trying to describe polymorphism and virtual tables is what always trips me.

[Adrir]

Originally Posted by yaustar

I had a quite a large range of tests. Some were relatively straight forward while some were plain evil (who uses C and ASM anymore on a a day to day basis?)

Trying to describe polymorphism and virtual tables is what always trips me.

That's quite interesting...all I know about vtables are that they are slower than regular function calls since you have to calculate the actual class/subclass implementation to execute. Do employers expect applicants to delve under the hood of these languages? What next? An in depth explanation of the Shader Model 4.0 pipeline?

[Gshonk]

Here is a useful book I use to prep for interviews .

I for one have a had a verity of different questions asked (and HAVE asked), from making a basic string reverse function, to drawing the UML for a basic game. Generally questions on the phone are more about what you know about the language you are going to be using. For example explaining the main features of OOP pogramming (wikipeadia is good here just follow all the links in this article.). I have had questions about the V-table but generally they are just "When does it come into play?" (when using the virtual keyword ). There are also generally some vector math questions.

[Aylwin]

I just had a technical test a few days ago. I wasn't worried about object-orient programming principles at the concepts are well ingrained into our program at school. I was more worried about remembering all the possible data structures and common algorithms. Unfortunately the stuff I prepared for was not in the test, instead they were questions like "What does this program print?" type questions, and the programs would have loops and/or predicates to see if you understood exceptions and the language. The second part of the test, which I haven't taken yet, is implementing a pac-man game from a given framework.

I guess I should brush up on my math as well!

[yaustar]

Originally Posted by Adrir

Do employers expect applicants to delve under the hood of these languages? What next? An in depth explanation of the Shader Model 4.0 pipeline?

Some can/will do. Depends how evil they feel.

[Hairdo]

Hi guys,

As everyone else said, the technical tests can be quite different. It depends what the studio wants to achieve. Some will make a relatively easy test if you know your stuff. Their goal is to test your knowledge, not to beat you down. Some, on the other hand, will hand out an impossibly difficult test. Something so hard, you cannot answer everything. The goal here is to put you under pressure and see how you react to that. They also want to know if you give up easily when stuck, if you propose alternatives...

I have passed a few technical tests in my career so far, there are 2 kind I’ve got. The interactive and non-interactive one. In the non-interactive one, you are locked in a room for 2 hours with the test and you try to answer as many questions as you can. In the interactive version, the interviewer sits with you and you go through the test together. The interviewer can then see how you react under pressure, how you solve the problems, what’s the path you took to reach the destination. Here, it’s important to vocalize what you think. Even if you are stuck on a question and can’t answer it, just tell the interviewer what’s going on in your mind and he will most likely give you tips to solve the problem.

I’ve also been in the interviewer seat and I was more interested by the person’s personality and attitude than by his test. The technical stuff can be taught or learned. The attitude and personality are harder to change.

I think I will write a more complete article on this subject on GameIndustryGrunts.com, but for now, off the top of my head:

Code/C++:
• What is polymorphism
• What’s the danger of multiple inheritance
• What is the difference between a macro and an inline function. Which one is best?
• What is a virtual function. What is a pure virtual function.
• What is an abstract class
• Here is some code. It crashes. Why? (Copy constructor stuff)
• Here is some code. It doesn’t compile. Why? (objects instantiation stuff)
• Write a function to… do something (reverse a string, write itoa, swap numbers..)
• Lots of const questions. (const functions, const pointer, etc)
• What’s the difference between ++i and i++
• Here’s a function. How would you optimize it?
• Here’s some buggy code. Find all the errors.

Math:
• What is an unit vector. Why is it useful?
• What is the result of a cross product
• What happens if you cross product 2 parallel vectors
• How would you normalize a vector
• What is a quaternion? Why use it instead of Euler angles?
• How would you do a ray vs plane collision check
• What is a AABB? Why use it?
• Here’s the UML diagram of some system. What does it do?

Games / 3D
• What is an octree, a quadtree or a BSP
• Describe the portal rendering technique
• What is the fill rate
• Draw the state machine of an enemy AI looking for the player. Mode: Idle, pursue, attack, die.. etc
• What is overdraw, why is it bad?
• What is culling, what is clipping
• What is the view frustum.
• What data structure would you use to store the inventory of some guy + longer description of the problem. (There’s no right answer here. What the interviewer is probably looking for is the pros and cons of data structures that could do the work.)
• What is pathfinding

Logic:
• I got this question once : Write a function that takes three integers corresponding to the lengths of sides and returns what kind of triangle can be made out of those 3 sides. (Equilateral, etc) You must also handle the case where no triangle may be formed from those 3 lengths.
• Imagine you have a closet full of shirts. It’s very hard to find a shirt. So what can you do to organize your shirts for easy retrieval?

something like that

[brainydexter]

Wow, this has inspired me to read more! Even though I took my algorithms and data structures exam @ school today, I still am thinking about the 'easy retrieval shirt' stuff, heh.

Need more knowledge, need more knooowledge