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Their recruitment process is deliberately containing a backdoor of knowledge of test vectors which change complexity of the exam from non-feasible in given time (2.5h) to actually quite easy.
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The screening is based on solving Codility tasks which were custom-tailored for the company, of which already the first programmatic is so ill-posed that you CANNOT solve it on time in general case unless you lower the quality by ignoring several possibilities, thus seriously lowering the code quality to the point it might or might not pass their final test vectors.
You COULD solve it on time being narrow-sighted, hasty, or lucky desperate student, or HAVING PRIOR KNOWLEDGE about what the actual tests used for scoring will be.
Bear in mind this is a test presented to C++ embedded developer with 20 years of experience - you would rather expect feedback about incomplete job by software specification team with analysis rather than see narrowed-down school style solution.
So, I did the general solution, as this task consumed 110% of total time allowed, sent the general solution in attachment via email (first quiz section done 100%, second task sent after time limit and observing what happens - for me it is a BROKEN TEST).
They have rejected me based on score by Codility and ignored my remarks (automated answer). I saw this or very similar question before, made remarks like 4 years ago (probably same company, don't remember), they ignored it once (since surely there are guys who can pass it 100% in given time - you just have to know what are input vectors for scoring and ignore all the pitfalls).
Expected outcomes:
They are grateful and they correct the task according to my assessment, then
a. they invite for another test, with different set of questions (impossible, since apparently the same task hangs around for years maybe with minor variations, and nobody complains)
b. They politely refuse to hire, but they correct the question or exclude it in the future and invite to try again
c. They ask to sent remaining solutions, as it would probably improve their question database and I would do it for fun at that stage.
Actual outcome: automated feedback of rejection, no answer from recruitment team, no contact for feedback for the rejection email is possible.
My opinion:
Their recruitment process is deliberately containing a backdoor of knowledge of test vectors which change complexity of the exam from non-feasible in given time (2.5h) to actually quite easy.
Side note, given like 5h I would have surely done 100% all tasks, unless there is one more stuff like that hidden in the other questions. And yes, I have solved the other Codility lessons on which I wasted a few days.
My diagnosis is that the test since many years is deliberately narrowing the selection to candidates who don't care about code quality but focus on scoring from luck, a culture that quality-minded person would not adopt, but an ideology of scoring that is very often adopted in Asia (deliver a gun = fine! nobody said it has to have a hole in the barrel).