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How does this code TLE aka Iteration over set/multiset not linear?
By Filikec, history, 8 hours ago, In English

I submitted this 311120546 solution to the recent contest Educational Codeforces Round 176 (Rated for Div. 2).

I was pretty sure my solution is N^2, and I didn't see a reason why it should TLE. Right after submitting I was a bit surprised that the solution took like 1.5s but I thought whatever, there's no way it gets TLE.

How come this code takes over 2s? The only explanation I can see is that the iteration over multiset is not linear which is what I thought for quite a long time.

UPD1: The TLE is because of using a list??? When I use a vector instead, it passes in 500ms

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5 hours ago, # |
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Auto comment: topic has been updated by Filikec (previous revision, new revision, compare).

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5 hours ago, # |
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[redacted because i was wrong]

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    5 hours ago, # ^ |
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    But I'm not sorting the list

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      5 hours ago, # ^ |
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      I take that back apparently sorting lists is actually $$$O(n\log{n})$$$ time

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4 hours ago, # |
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Why would someone ever use lists in CP when vectors do exist?

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    3 hours ago, # ^ |
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    To be honest I never found a problem that can be solved with a list and not be solved with the other data structures.

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3 hours ago, # |
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Generally if a problem can be solved in much lesser time complexity then there will be a test — case that pushes the unoptimized codes/approaches to TLE. It was supposed to be done in O(n log n), using either sorting or Max-Heap. N^2 is much more complex. That's why it resulted in TLE.

Also about list vs vector, list uses linked list which has higher access complexity. Vector has O(1) due to indexing.

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