Here is my part 2 follow up from Oddball Questions Part 1.

These are my responses to the Top 25 Oddball Interview Questions from Glassdoor, presented in Snappy Answers format.

Snappy Answers 13-25

13. “Name 5 uses of a stapler without staple pins.” – (EvaluServe)

Snappy answer: Entirely useless. See also: caffeine-free coffee and alcohol-free beer.

Alternatively (1) dental drill (2) geosynchronous satellite (3) pizza cutter (4) forklift (5) crampon.

14. “How much money did residents of Dallas/Ft. Worth spend on gasoline in 2008?” – (American Airlines)

Snappy answer: About $3.00 a gallon?

15. “How would you get an elephant into a refrigerator?” – (Horizon Group Properties)

Snappy answer: Cuisinart (The easy answer – this question is the subject of some amusing math responses)

16. “You have a bouquet of flowers. All but two are roses, all but two are daisies, and all but two are tulips. How many flowers do you have?” – (Epic Systems)

Snappy answer: None, I tossed them out after they wilted.

17. “How many planes are currently flying over Kansas?” – (Best Buy)

Snappy answer: Euclidean or Cartesian?

18. “How many different ways can you get water from a lake at the foot of a mountain, up to the top of the mountain?” – (Disney Parks & Resorts)

Snappy answer: Infinite number of ways. Isn’t that obvious?

19. “What is 37 times 37?” –(Jane Street Capital)

Snappy answer: BD1

20. “If you could be a superhero, what power would you possess?” – (Rain and Hail Insurance)

Snappy answer: The power to end senseless interviews in a single bound!

21. “If you were a Microsoft Office program, which one would you be?” –(Summit Racing Equipment)

Snappy answer: Notepad.

22. “Pepsi or Coke?” – (United Health Group)

Snappy answer: Yes please.

23. “Are you exhaling warm air?” – (Walker Marketing)

Snappy answer: Get your hand off my leg, you pervert.

24. “You’re in a row boat, which is in a large tank filled with water. You have an anchor on board, which you throw overboard (the chain is long enough so the anchor rests completely on the bottom of the tank). Does the water level in the tank rise or fall?” – (Tesla Motors)

Snappy answer: If the anchor is thrown far enough so it clears the side wall of the tank, the level will rise. If the anchor consists of a massive sponge larger than the tank, then the level will fall.

25. “How do you feel about those jokers at Congress?” – (Consolidated Electrical)

Snappy answer: They’re not nearly as funny as I am

One item I really enjoyed was Al Jaffee’s Snappy Answers to Stupid Questions, and those come to mind as I continue my thread on interview questions.

Oddball Questions

Glassdoor recently had an article titled Top 25 Oddball Interview Questions.

Oddball, indeed.  In reading them over, was sorely tempted to answer them with “snappy answers”.  Here are a few for your amusement.

The original questions from the article are in this color.  The snappy answers are basically what occurred to me when I first read the question.

Snappy Answers 1-12

1. “How many people are using Facebook in San Francisco at 2:30pm on a Friday?” – (Google)

Snappy answer: All of them.  It’s San Francisco.

2. “Just entertain me for five minutes, I’m not going to talk.” – (Acosta)

Snappy answer:

3. “If Germans were the tallest people in the world, how would you prove it?” – (Hewlett-Packard)

Snappy answer: Measure all instances of Germans pairwise against all other humans by transporting them all to Düsseldorf and placing them back-to-back in the Marktplatz . This means measuring all 81 million Germans against the other 7 billion inhabitants. This only requires worst case  67,000,000,000,000,000 comparisons and hence is computationally efficient. We can accomplish this in a few hours on a dual core Pentium, though it may require a little more time on an Apple ][ running iOS.  If all Germans are pairwise taller than all other humans, it is proven.

4. “What do you think of garden gnomes?” – (Trader Joe’s)

Snappy answer: White hat or black hat?

5. “Is your college GPA reflective of your potential?” – (Advisory Board)

Snappy answer: Not sure why they would be related.  To measure my potential, I recommend a voltmeter.

6. “Would Mahatma Gandhi have made a good software engineer?” –(Deloitte)

Snappy answer: Unlikely. This great man passed in 1948, only two years after the debut of ENIAC.  Though Turing complete, programming the ENIAC was pretty far removed from what we now call software engineering.

7. “If you could be #1 employee but have all your coworkers dislike you or you could be #15 employee and have all your coworkers like you, which would you choose?” – (ADP)

Snappy answer: If the company has fewer than 15 employees, I’d choose #1.

8. “How would you cure world hunger?” – (Amazon.com)

Snappy answer: First solve for global conflict; this generalizes to solve world hunger by side effect.

9. “Room, desk and car – which do you clean first?” – (Pinkberry)

Snappy answer: Work from home.

10. “Does life fascinate you?” – (Ernst & Young)

Snappy answer: Very much so! I particularly like the Gosper glider gun.

11. “Given 20 ‘destructible’ light bulbs (which breaks at certain height), and a building with 100 floors, how do you determine the height that the light bulb breaks?” – (QUALCOMM)

Snappy answer: Drop one from the 100th floor.  If it breaks, you have found a height at which it breaks.  If compact fluorescent, report to the EPA.

12. “Please spell ‘diverticulitis’.” – (EMSI Engineering)

Snappy answer: P-I-T-A

More soon.

A few years back, a colleague asked me to ponder a Wizards and Dwarves puzzle as a potential interview question.  A typical statement goes something like this:

A village of wizards is nearby a village of dwarves.  Once a year, the wizards visit the dwarves, and line up the dwarves in increasing order of height, so that each dwarf can only see the dwarves smaller than himself.

The wizards have white and black hats.  They place a white or black hat on the head of each dwarf (using a strategy of their choosing, perhaps even randomly).  Then starting at the back of the line (the tallest dwarf), they ask each what color hat he is wearing. 

Each dwarf who answers incorrectly is killed by the wizards.  The other dwarves can hear his answer, but do not know whether he was killed.

What strategy minimizes the number of dwarves killed?

Ok, I thought about it.

Pondering

Among many irritations I have for puzzle questions, the fiction is frequently distracting: 

Why villages?  Why wizards and dwarves?  Why in order of height?  What if they are all of the same height?  How can you kill a dwarf and not have his neighbor nearby hear it?

And my brain spins with other tangents:

Dwarves have high magic resistance and constitution – don’t they get a saving throw?  Toss in a few +5 battle axes and there would be a wizard slaughter!

Meh.

Wizards, Dwarves and Barometers

In the spirit of the barometer question, I formulated the following responses:

• Non-violent non-cooperation.  It is not stated that there is a penalty for non-cooperation.  In the spirit of Gandhi, the dwarves refuse to be sorted by height, do not line up, and will not wear hats.  Wizards are known weaklings and will be unable to forcefully move the dwarves into place.
• Scatter.  The dwarves split their village up into smaller villages, until each village consists of a single dwarf.  Each dwarf now has an equal chance of survival (this strategy, while fair, will be popular with the tall dwarves, but less so with the short ones).  The maximum number of dwarves killed will always be one.
• UN Convention on Genocide.  The dwarves are being unfairly singled out as a group for destruction.  Citing Resolution 260 (III), they appeal to the United Nations and await protracted discussion.
• Mini-guns.  Despite their diminutive size and desire peace, the dwarves obtain special weapons training, obtain mini-guns and when threatened, and whoop some major wizard ass.
• Mobile Phone.  First variant – dwarf uses a mobile phone to take a picture of his hat, revealing the color.  Second variant – dwarf snaps a photo of the dwarf in front of him and texts it to him.
• Low tech (no mobile phone required).  Dwarf turns around and asks the dwarf behind him the color of his hat.
• Vacation.  The wizards arrive once a year.  The dwarves arrange to be out of town on that day (ideally somewhere warm and sunny).
• Insubordination.  Each dwarf takes off his hat and reports its color.

And so on.

Conclusion

If you follow the intended script, you can find solutions in which no more than one dwarf is killed (the tallest has no knowledge of his hat color and his odds are essentially subject to chance).

But as shown above, one can simplify and further optimize the solution by exploiting ambiguities in the fiction.

And it’s a lot more entertaining.

A young fellow interviewing me asked a reasonable set of basic technical questions, had me code a few things on the white board (also reasonable), and so on.  The interview was pretty typical, and going well.

Near the end, he looked at me slightly askance, and said

“Ok, now I’m going to ask you a puzzle question.”

I may not have successfully resisted the temptation to roll my eyes as I responded

“Mmm, Ok.”

I’m not very fond of puzzle questions.

Barometers

He proceeded to ask

“Suppose you spot a building in the distance and want to estimate its height.  How would you do that?”

I chuckled and replied “That really reminds me of The Barometer Question.”  He blanched a bit and asked “What do you mean?” 

He hadn’t ever heard of it.

I proceeded to relate the story of the professor who asks a student how to measure the height of a building “with the aid of a barometer”.  The professor’s expectation is that student will provide an answer involving differential pressure from the base to the top. 

Instead, the student provides a list of unexpected, yet technically correct answers:

• Tie a string to the barometer and lower it from the top of the building until it touches the ground.  The length of string will be the same as the height of the building.
• Toss the barometer off the top of the building, time how long it takes to hit the ground, and solve for height.
• Offer the shiny new barometer to the building superintendent in trade for a peek at the blueprints.  The building height will be on the blueprints.

and so on.

“Wow, sounds like you’ve already heard of that one …”

said my dismayed interviewer.  (Indeed, though we eventually discussed the question and I provided him with a novel answer that satisfied him.)

Wizards and Monkeys

As puzzle questions go, this barometer variety isn’t too bad – at least it is amenable to multiple alternative, creative and valid solutions.

Puzzle questions which primarily involve a “gotcha” moment of perfect truth are in my mind essentially worthless for evaluating candidates.  In this category I have in mind classics such as Wizards and Dwarves, or the one on Monkeys and Switches.

These questions tend to result in a quick response if the candidate has heard them before, or a lot of fruitless struggling if they have not.  They generally don’t lend themselves well to systematic analysis nor extended discussion.

The puzzles are entertaining, for sure, but do you want to hire someone who can solve brain teasers, or do you want someone who can actually get work done?  Unless perhaps you run a company that authors brain teaser books …

In Joel Spolsky’s widely referenced article on Guerilla Interviewing, he too frowns on what he refers to as “Aha!” questions (the “gotcha” questions I refer to above), for similar reasons.

Out of the Box

Joel hedges somewhat more on what he calls “impossible” questions, like “How many piano tuners are there in Seattle?”  I’m a little more sympathetic here – I call those “out of the box” questions since you’re essentially looking for a candidate to approach a non-standard situation in a systematic way.

While I find those questions slightly more useful, they are less relevant for programmers than fundamental questions on algorithms, data structures, coding, design and architecture.  And in a 45-60 minute interview, I find I’m already pressed for time to cover those well.

As a result, if I’m ever interviewing you and ask you a puzzle question, it’s only because you’ve done very well.  It means I’d like to hire you, the interview is ahead of schedule, and I’m simply curious to see how you respond.

I’m secretly hoping you’ll roll your eyes, of course …

And if you ever ask me a puzzle question in an interview, I’m making a mental note to follow up (if hired) and speak to you about your interviewing techniques.