about the probabilities: say Steve's number is 59. I say 50, Steve says higher, so there are just 50 numbers left and the new probability is 1/50, I say 75, Steve says lower, so the probability is 1/24 (otherwise it would be 1/25), and so on
Steve Ballmer's incorrect binary search interview question
141–150 of 257 posts
Re: Steve Ballmer's incorrect binary search interview question
#142I wrote similar code to show that as long as you choose your starting number randomly you will have positive EV. Not sure how they kept using this interview question without realizing this.
Re: Steve Ballmer's incorrect binary search interview question
#143Earlier quoted context omitted.
> if you perform a character edit format instruction in EBCDIC mode with the leading zero specifier and the numeric value is too great to fit into the allocated field, after the instruction completes, what is the state of the program status word overflow field? "Is the computer operating on American electricity, or European?"
African or European. Everyone knows that.
African and European electricity could be operating it together...
Re: Steve Ballmer's incorrect binary search interview question
#144Earlier quoted context omitted.
That SME guy sounds like an asshole, but I used to have an interview technique where I’d ask increasingly specific and low level questions about the candidates area of expertise until it got to the point where I’d be pretty confident they wouldn’t know the answer off the top of their head. I wasn’t adversarial or rude about it, I just wanted to find out if they were comfortable saying “I don’t know”, because not know…
They don't know what the interviewer wants to hear. There are places where every admission of not knowing something is held against you.
If the employer would hold that against you, it's not a place I'd want to work. Not sure about you.
Re: Steve Ballmer's incorrect binary search interview question
#145This is a game with imperfect information, and the optimal strategy for each player is probably different from "pick any number at random" and "run off-the shelf binary search".
How is it imperfect information? Isn't each guess made openly?
Re: Steve Ballmer's incorrect binary search interview question
#146Earlier quoted context omitted.
I had an interview at a major tech company with a similar thing, for a more managerial role. The question was to estimate how many vacuum cleaners there were in the city we were in. Fine, I did some estimation of how many vacuum cleaners per household and per office, across how many households and offices. Standard stuff. Then the guy starts laughing and saying I'd failed because I didn't include discarded vacuum cle…
Is the landfill actually 'in' the city, or in a rural area outside the city limits? I had a similar interview years ago - something like "how many windows are there on houses in our town?". Wasn't quite that, but I asked up front if "houses" meant just physical standalone houses, or if they meant living spaces, including apartments/dorms, etc. I got clarification, gave some estimate with some reasoning, and was then…
Yes, I have used questions like this before for junior roles and the notes for the interview were something like:
- Asked/did not ask clarifying questions
- Did/did not (or could not, on prompting) verbally walk through their reasoning
- Could/could not articulate which assumptions they felt were most important/why
Nothing about the actual content of the question itself, or if your answer was approximately correct (I usually did not know even the ballpark of the correct answer myself). I will say I did sometimes write down if candidates make comically bad assumptions. Like assuming the population of the USA was 1 Billion people. It's a fine line on what is "comically bad" but like, if you are interviewing for a startup of 20 people and you use $20B/year as the revenue assumption with no wink. That's a red flag. Lmao.
Re: Steve Ballmer's incorrect binary search interview question
#147Earlier quoted context omitted.
"as you, my interviewer, are a capable SWE I assume you gave me all the context needed to solve the problem". The interviewing game of asking clarification questions is silly and should stop. In the system design portion I can understand it, but not when asked a direct technical question. It's perfectly fine to ask followup questions with added constraints or just directly say that the specification is fuzzy and need…
> but not when asked a direct technical question. This is anything but a direct technical question though. > It's perfectly fine to ask followup questions with added constraints, but having the guessing game to figure out those constraints is nonsense. You say that. I say people being able to ask the right question is one of the most important skills to be a productive developer. So of course as an interviewer I want…
> I say people being able to ask the right question is one of the most important skills to be a productive developer.
But you never know if by asking the "right" question you'll jeopardize the entire interview problem. Some interviewers may have only prepared 75% of the problem and haven't went through all the posibilities. If you ask a question that may pose itself as a "treat" (e.g., making half the problem non-sense and therefore there's no need to implement it) your interviewer may simply consider you a no-go.
And it's not about malice, but simply that you may be better prepared than the interviewer and some times that leads to a no offer. I wouldn't mind working in a place like that, so I don't usually ask "too clever" questions.
Re: Steve Ballmer's incorrect binary search interview question
#148I recently interviewed for a senior level role for a complex domain (payments), this is an area I have more than a decade of experience. The interviews went flawlessly because I know payments inside out, not just in US but in UK and most EU jurisdictions. The funny bit is that the role being senior, influencing, soft communication skills and managing conflict are even more important than the subject matter expertise…
That SME guy sounds like an asshole, but I used to have an interview technique where I’d ask increasingly specific and low level questions about the candidates area of expertise until it got to the point where I’d be pretty confident they wouldn’t know the answer off the top of their head. I wasn’t adversarial or rude about it, I just wanted to find out if they were comfortable saying “I don’t know”, because not know…
I have the same idea in interviews. they need to be able to admit when they don't know or need help depending on the level. However I thought about it and I think the continuous "why" comes off as sort of childish or low effort. I didn't want to drive off people that reasonably didn't want to work in a place with a toxic culture. My solution was to ask a question that was specific to the workplace but technical so that it would require more information to solve. I looked for answers along the lines of:
- I don't know - I don't have enough information based on the question - I would do it this way generally but this question requires employer specific information.
Not someone that just barreled forward and came up with a defacto answer as the solution. They had to give some sort of admission that they could not really solve the problem as is.
Re: Steve Ballmer's incorrect binary search interview question
#149Earlier quoted context omitted.
Is the guy's response really that far off? Each router checks its table for the destination, and if it doesn't know it, queries the next upstream router, its default route, the next hop. Each router likely ultimately informs you of the hand-off via a packet of some sort, and your then traceroute sends a ping/ICMP to each hop to learn how far away they are. He maybe could've been pushed to expand on what he did know i…
The stepwise increasing TTL is the fundamental mechanism that makes traceroute work. Any answer that omits this is so vacuously incomplete that it might as well be considered wrong.
fair enough, I guess the TTL exceeded response is how you learn about each hop
Re: Steve Ballmer's incorrect binary search interview question
#150How you end up hiring a mathematician while looking for a programmer.
This can be a big problem in teams that are homogeneous: All were hired using the same process, so all are maths/physics majors with good analytical skills but insufficient software engineering skills.
What often happens maths/physics majors excel at programming the small, but cannot architect things in the large. As a friend once put it about one such person: "He can only do it as long as he can fit the whole problem in his head at once."
It's great to have mathematicians and physicists in the team. But you for sure want a sufficient number of trained and experienced software engineers as well.