l_l's blog

Problem 547C "Wrong answer on test 3"
By l_l, history, 10 years ago, In English

Hello,

I have solved Question 547C, but when I submit my answer it gives me runtime error for gnuG++11 and wrong answer on test three for gnuG++ even though the test case works for me.

Here's a link to my submission:

http://mirror.codeforces.com/contest/547/submission/11443674

Basically, my approach to this problem is that I save the relation between all foam heights (whether coprime or not) in a two-dimensional vector "bool coprime". Then using that info I update the new score by calculating the difference in score after a beer is placed or removed. The time complexity of this approach is O(n^2).

I would appreciate it if anyone can figure out what's going on.

Thanks

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10 years ago, # |
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__gcd(x, 0) causes undefined behavior .... implement your own gcd. see here

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10 years ago, # |
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Even if it passed Test #3, your solution will definitely time out in a later case. O(N2) for N = 2 * 105 would take like 7 minutes to run, let alone that it would use over 40 GB of memory.

I'd look for a different approach instead of trying to find the bug on that one.

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    10 years ago, # ^ |
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    Thnx.

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    10 years ago, # ^ |
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    By the way how did you calculate the time it takes. I'm just curious for future problems. Thanks again

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      10 years ago, # ^ |
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      Well, that depends on the CPU you run the program on, but as a general rule, divide the number of operations by 100M and you'll have an estimate of how many seconds it will take.

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