The Power of Pressure

The other day I was, relatively speaking, very close to landing a good job in the software industry. However, during the last 5% of the interview process pressure kicked in and my mental processes collapsed, leaving me starring at the white board unable it seemed, to even spell my name.

At this point it had already been a surprisingly long recruiting process, consisting of more than 8 hours of problem solving interviews. I’d had a break for the weekend, and was now called in for a final interview with the big boss. This was of course an indication that they were considering me seriously, however the recruiting agent had let me know that a few of the interviewers had expressed a wish that I’d been a bit faster at coming up with solutions.

The first half hour with the big boss went well, focusing more on me being a cultural fit than technical skill. But then, for the last half hour he suddenly asked me another problem solving question: implement method transposeMatrix(int[] matrix, int n) where the matrix is assumed to be of size n by n represented by a one-dimensional array, and with only a constant memory overhead (so no allocation of another array).

I quickly realised how the algorithm would work, using two pointers running respectively out of the rows and down the columns. However, when it came to writing the code I froze up — and not because it’s difficult code, but because I knew that me getting the job or not most likely came down to these particular 30 minutes. As a result, I got self-conscious and my focus started drifting away from the white board towards the big boss looking over my shoulder.

The outcome was that I turned completely blank, fighting to bring back focus where it was desperately needed. But it didn’t happen until after 20 minutes of nonsense, when I got a 5 minute break while he left to pick up a new whiteboard marker. When he came back my focus was there already and the solution came quickly:

void transposeMatrix(int[] matrix, int n) {
    for (int row = 0; row < n-1; row++) {
        for (int col = row+1; col < n; col++) {
            int i = row * n + col;
            int j = col * n + row;
            // swap matrix[i] and matrix[j]

yet it was too late; given the performance I illustrated that day I wouldn’t have hired myself, so in full understanding of their decision.

The frustrating part instead, is that this can still happen to me when I want something badly (it never happens when I don’t care). But what’s to learn from this? Well, I’m better at problem solving with a piece of paper in front of me and 5 minutes of “quite time”; I’ve been hesitating to take this at interviews for a fear of disrupting the flow, but it seems it can come to a point where it’s worth it. Also, I’ve started on ways of controlling nerves by basically caring less about the surroundings; since this is rooted in a current insecurity (from being unemployed?) it is easy to practise in everyday life.

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