[LargeTomato]

I worked at a rocket startup. 1/3 ex SpaceX. 1/3 ex Google/Facebook.

I interviewed a guy and asked him, essentially, "find the biggest number in a 2D array". This guy spent half an hour struggling because he "wasn't sure how to look through the grid in a circle pattern".

You'd be incredibly surprised who gets interviews.

[filoleg]

> "wasn't sure how to look through the grid in a circle pattern"

Now I am curious to know whether I am too dense to get it or if the candidate was just that off the mark.

Is circle pattern sorta like iterating through a 2d array like a spiral (i.e., outer layer of the 2d-shape first, then one deeper, etc.)? And if yes, why would that ever be useful for just searching for a specific value in a 2d array?

I get how it could be useful for some more niche/specific problems where the layering of the 2d array would actually matter, but is it just entirely off the chain to recommend it here? Because I cannot for the life of me figure out why you would want to do that instead of just iterating, especially considering how significantly less trivial it is to code-up that “circular” iteration (as opposed to just a regular linear iteration).

Sidenote: Is there even a more efficient way to solve that problem, other than just sequentially iterating through the 2d array and simply tracking the value/position of the largest number until you finish iterating over the entire 2d array (assuming it is non-sorted)? It seems way too simple, so I feel like either I am missing something about the problem statement or there is a better solution than the one I proposed.

[LargeTomato]

This was part 1 of a 2 or 3 part question. First we literally iterate through each element, keeping track of the max. I use this question for interns, too, so it's intentionally super easy. It gets harder in part 2.

For clarity, the pseudo code solution to the question is

    for row in a[0]:
        for e in row:
            max_so_far = max(e, max_so_far)
    return max_so_far

No tricks. Just an initial weeder question for interns before we move onto the real question.

[filoleg]

Ah, makes perfect sense, thank you for clarifying. Your pseudo code solution confirms that I understood the problem statement correctly.

Out of pure curiosity, what were the follow up (part 2 and 3) questions? Not looking for a solution, but if you could post the problem statement, it would be very appreciated. If you feel uncomfortable sharing it publicly out of some concern, that’s entirely fair, no worries.

[chrismcb]

I think the point of the OP was A the person wanted to solve this in a spiral pattern, which isn't necessary. And B didn't know how to do a spiral pattern, which is fairly simple. As to your other question, unless it is directed you need to look at each element. The real question is how to iterate over a 2d array. There are several methods and really that is all this question is looking for.

[icedchai]

Most day-to-day coding is simple and boring. Your interview questions should be, too. I've interviewed 100's of candidates over the years. Many of them had trouble writing a couple of for loops. This was for a somewhat similar problem. I would stress "we don't need an optimal solution, we just need a working solution."

[1920musicman]

Honestly, at this point I stopped making strong conclusions about candidates based on a single interview. I won't recommend to hire but also won't judge their abilities overall. Interviews can be very stressful, candidates overthink and often get fixated on a random solution they think the interviewer expects, etc.

I had several odd experiences myself in the past, as a candidate. The funniest one was when I interviewed at a prestigious company I thought was hiring only top talent. I spent an hour trying to come up with the most efficient Sudoku solver, got completely stuck on some arbitrary algorithm that I came up with on the spot. It wasn't a "circle pattern" but close to that. Wanted to impress the interviewer and also did not sleep the night before overthinking the process.