(note (code cslai))

Hitting a nail with the wrong hammer (my writing tools)

I just failed a programming assessment test miserably yesterday and thought I should at least document it down. However, the problem with this is that the questions are copyrighted, so I guess I would write it from another point of view. So the main reason I failed was because I chose the wrong strategy to the problem, thinking it should be solution but as I put in time to that I ended up creating more problems.

So there’s this script I wrote in the past to assist in my writing. I mostly write in Chinese, and the problem with my writing is that I tend to repeat certain words more than it should. Therefore in order to fix this, I wrote a script to generate something to list all the ngrams and (reverse) order them by the frequency of use.

So the core function that makes this possible is


function input_generate_ngram(Array $input, $n) {
    return array_reduce(
            range(0, count($input) - $n),
            function(Array $current, $next) use($input, $n) {
                return array_merge(
                    $current,
                    array(implode(NULL, array_slice($input, $next, $n))));
            },
            array());
}

What it does is that, given an array of words (Chinese character in this case) I can use this to generate an array of n-grams. For example, if I have send this as input (assuming $n = 2)

['今', '天', '天', '氣', '很', '好']

I would get

[['今', '天'], ['天', '天'], ['天', '氣'], ['氣', '很'], ['很', '好']]

The code itself is not written for efficiency, and could use some polish. However I am not publishing it because I am using it personally for my writing projects so I guess it is good enough. Tokenization is also not considered as I am not doing in-depth analysis to the text, I am not a linguist, and the script was used just to discover repetitive keywords.

So the assessment test was about a function that replace a string repetitively by following a set of rules. In order to not get too specific about it, think of this problem as simplifying a mathematical expression. For example in order to simplify (-(-x) * (-x) + y + (-y) / (-y)), we would perform a series of steps as follows


(-(-x) / -x + y + (-y) / (-y))
= (x / -x + y + (-y) / (-y))
= (-1 + y + (-y) / (-y))
= (-1 + y + 1)

So the rules here are obviously

So putting the expression into the function (again I can’t replicate the original problem so the example output here doesn’t make sense, just assume as it is), and set $n = 2


INPUT =['-', '-x', '+y', '+', '-y', '/-y']
OUTPUT = [['-', '-x'], ['-x', '+y'], ['+y', '+'], ['+', '-y'], ['-y', '/-y']]

So when I got really excited when I arrived this state. So I did all the match and replace, but a new problem came up when I attempted to merge the string together. Practically, I made a new problem by following this solution. However, I was too obsessed with the strategy then, so I kept on trying, and obviously I failed because once I got one case covered, then I got a new problem on its own.

In the end I got fed up and started again from fresh, however, it was already too late and I didn’t have the time to properly check it. Also due to the ticking clock I was unable to complete the question in time. So out of the three questions, I got none of them right (the first one was a bug fix, which I skipped at first, and this post is about the second one, I didn’t have time to read the third). The test was 90 minutes long, and should be sufficient if I wasn’t stuck in the wrong strategy. Guess I chose the wrong hammer to hit the nail, and paid quite a price for that.

So the point is, I am open for a new job opportunity, if you are interested leave me a message LOLOL.

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