priyanshu_28's blog

C++20 gives wrong answer
By priyanshu_28, history, 2 years ago, In English

During Educational Codeforces Round 116 (Rated for Div. 2), I try to submit my solution for question c in c++20 when there were around 850 submissions. But due to some reason, I kept getting the wrong answers. When I submitted it in c++17, it got accepted. You can see my submissions. Kindly look into this matter, I want to point out the bug rather than focusing on anything else. MikeMirzayanov

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2 years ago, # |
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What is the difference between log(k)/log(2) and log2(k)? Because in B problem it gives wrong answer if I use first one.

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    2 years ago, # ^ |
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    because C++ isn't your CASIO calculator, it has to work with precisions

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2 years ago, # |
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Most likely the pow function here is the culprit. Even if both of its arguments are integers, it still works with non-integer types, so it sometimes causes precision issues. Source

Your solution would've worked if you had made a power function of your own. Or what you did, shifting from 64bit to 32bit compiler.

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    2 years ago, # ^ |
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    The funny thing is if the compiler rounded down the value it makes sense. It actually printed a bigger answer.

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