Good day codeforces.↵
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I am currently preparing a problem where a variable must match one of the ten possible values. Once I finished the validator, I noticed that it validates unusually long, about 18 seconds. Meanwhile, my solution only runs in about 2 seconds on my local machine.↵
↵
After debugging, I found out that the problem is with readToken. I created a simple validator to reproduce the bug:↵
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Validator 1: https://ideone.com/1CZiQW↵
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Validator 2: https://ideone.com/d91Aan↵
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test-case used: https://files.catbox.moe/qb00ce.in (size: 5.2 MB)↵
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What both of them do is read an input file where the first variable (cmd) can be one of ten values (QUERY1 — QUERY10). Their running time differ vastly.↵
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Validator1:↵
↵
↵
~~~~~↵
time ./a.out < testcase.in↵
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real 0m16,480s↵
user 0m16,465s↵
sys 0m0,009s↵
~~~~~↵
↵
↵
↵
Validator2:↵
↵
~~~~~↵
time ./a.out < testcase.in↵
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real 0m1,667s↵
user 0m1,662s↵
sys 0m0,005s↵
~~~~~↵
↵
As we can see, Validator2 is almost ten times faster than validator1. Is there a caveat on readToken() which makes it slow to validate multiple patterns? i tried readToken([A-Z0-9]*) and it gives compatible results to validator2.↵
↵
Thank you for your time, and have a nice day :)↵
↵
Edit: im also wondering. 1.6 s just to read input is a bit slow for C++, no? Is there anything else that can be improved here?↵
↵
I am currently preparing a problem where a variable must match one of the ten possible values. Once I finished the validator, I noticed that it validates unusually long, about 18 seconds. Meanwhile, my solution only runs in about 2 seconds on my local machine.↵
↵
After debugging, I found out that the problem is with readToken. I created a simple validator to reproduce the bug:↵
↵
Validator 1: https://ideone.com/1CZiQW↵
↵
Validator 2: https://ideone.com/d91Aan↵
↵
test-case used: https://files.catbox.moe/qb00ce.in (size: 5.2 MB)↵
↵
What both of them do is read an input file where the first variable (cmd) can be one of ten values (QUERY1 — QUERY10). Their running time differ vastly.↵
↵
Validator1:↵
↵
↵
~~~~~↵
time ./a.out < testcase.in↵
↵
real 0m16,480s↵
user 0m16,465s↵
sys 0m0,009s↵
~~~~~↵
↵
↵
↵
Validator2:↵
↵
~~~~~↵
time ./a.out < testcase.in↵
↵
real 0m1,667s↵
user 0m1,662s↵
sys 0m0,005s↵
~~~~~↵
↵
As we can see, Validator2 is almost ten times faster than validator1. Is there a caveat on readToken() which makes it slow to validate multiple patterns? i tried readToken([A-Z0-9]*) and it gives compatible results to validator2.↵
↵
Thank you for your time, and have a nice day :)↵
↵
Edit: im also wondering. 1.6 s just to read input is a bit slow for C++, no? Is there anything else that can be improved here?↵
