neal's blog

Why is this submission so slow? D2. DFS Checker (Hard Version)
By neal, history, 6 weeks ago, In English

Can anyone tell me why this submission is so slow? 275858049

It's $$$\mathcal{O}(N + Q)$$$ and should be very fast, but somehow it takes 1125 ms.

Meanwhile my in-contest code that uses lots of sets and does a bunch of nonsense only takes 561 ms: 275858229

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6 weeks ago, # |
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Seems like it has something to do with the compiler as its ~300ms on C++17.

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6 weeks ago, # |
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I think it is something related to this blog: Slowdown bug affecting C++ (64 bit).

You can also check this weird TLE I got in Codeforces Round 899 (Div. 2).

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