Steve Ballmer's incorrect binary search interview question
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Re: Steve Ballmer's incorrect binary search interview question
#2Didn't Steve Ballmer start off at MSFT essentially in a biz ops role, supporting execs when the company was super small? Interesting how he became technical as the company grew. Pretty rare.
Re: Steve Ballmer's incorrect binary search interview question
#3Title is wrong in implying Balmer is incorrect and the article shows that the title is wrong. If clickbait is misleading, then this is worse than clickbait, no?
> Ballmer states that the answer is "No" for two reasons: firstly, because he can pick numbers that'll be the most difficult for you...
The article goes on to show that there are numbers where a binary search always has the guesser paying $1
Re: Steve Ballmer's incorrect binary search interview question
#4This write-up makes the erroneous assumption that he's choosing randomly. He himself says, in this same write-up, that he's choosing adversarially.
Nice write-up anyway, and yes, Ballmer is wrong.
Re: Steve Ballmer's incorrect binary search interview question
#5Didn't Steve Ballmer start off at MSFT essentially in a biz ops role, supporting execs when the company was super small? Interesting how he became technical as the company grew. Pretty rare.
> Didn't Steve Ballmer start off at MSFT essentially in a biz ops role
Yes, business manager.
> Interesting how he became technical as the company grew.
That's not clear from this. This shows he knew some concepts as part of managing different teams in the company.
Re: Steve Ballmer's incorrect binary search interview question
#6I'm so glad I've managed my career such that I've never had to answer bullshit interview questions like this. The only purpose of these is to stroke the asker's ego, they tell you nothing at all about the candidate. What a waste of time.
Re: Steve Ballmer's incorrect binary search interview question
#7Didn't Steve Ballmer start off at MSFT essentially in a biz ops role, supporting execs when the company was super small? Interesting how he became technical as the company grew. Pretty rare.
He graduated with a mathematics degree from Harvard so the concept of binary search would have likely been familiar to him. But you’re right, as far as I can tell, he never did any technical work like programming in his career.
Re: Steve Ballmer's incorrect binary search interview question
#8The (TV) interview is kind of funny because the journalist asks him, after he goes through the idiotic song and dance of this brain teaser: "so what did you learn about me?" This is actually a very insightful question. What did you learn, Mr Ballmer?
To which he literally has no answer: "I learned you need to step back and really ask if you're going to make money on this thing".. uh, okay Steve. Cool. Thanks for your contribution to possibly the worst technical hiring practices in just about any professional field. The technicals are less interesting than seeing even he himself has no real justification for this kind of intellectual hazing.
Re: Steve Ballmer's incorrect binary search interview question
#9Title is wrong in implying Balmer is incorrect and the article shows that the title is wrong. If clickbait is misleading, then this is worse than clickbait, no? > Ballmer states that the answer is "No" for two reasons: firstly, because he can pick numbers that'll be the most difficult for you... The article goes on to show that there are numbers where a binary search always has the guesser paying $1
But if you know the number picker is going to choose these numbers you can optimize your algorithm.
Re: Steve Ballmer's incorrect binary search interview question
#10The article implies that the interviewee assumes that the number is being chosen randomly, when Ballmer could actually be choosing adversarially.
However, if the interviewee assumes that Ballmer is being adversarial, then you can pick a different value as your initial guess, which causes the probabilities to shift. Even the OP assumes that the interviewee will start guessing with 50, but, because of the way binary search works, you can select an initial guess that is offset from 50 (with a randomized offset each time) to defeat trivial adversarial attacks that attempt to game the heuristic, while still mostly reaping the benefits of binary search.
I'd be interested to see someone do the analysis of what the optimal random-offset-selection algorithm would be to counter trivial adversarial choices.