I'm glad you ask this, as it signals very clearly the need to get up and walk out of the room.

Same with your last sentence.

> "What number am I thinking of?"

I don't think this is a good interview question, but I do think it is interesting as a thought exercise.

I bet that perhaps 25% of candidates could actually answer the question correctly, even if they didn't know anything about Schelling points. It could also lead to some nice discussions about how to solve an open-ended problem, probability distributions, strategies for maximizing payoffs when making decisions in the face of uncertainty, and so on. The question is so bad, it's actually kind of good.

The solution to this entirely depends on whether you are willing to answer other questions about the number and of what nature. Would you answer: is it higher/lower than X? How about how many digits there are?

But assuming you are unwilling to answer any additional questions, the correct solution is to simply brute force every number up from 0 and its negative.

    % isIt3
    10
    0
    6
    4
    8
    0
    9
    5
    I found three
    ----
    proc isIt3 {} {
     variable 3 [expr {int(rand()*12)}]
      switch $3 {
       3 { puts "I found three" }
       default { puts "$3" ; isIt3 }
      } ;# end switch
    } ;# end proc

The number you're thinking of is 3. (-:

So how well would a candidate do if they looked at that and thought "whoa, is Tcl really tail recursive?!"

_thinks: "gotta be a sarcastic comment"_

What answer are you looking for?