DimmyT's blog

By DimmyT, history, 21 month(s) ago, translation, In English,

On task 977F - Consecutive Subsequence I have a TL on solution with unordered_map 37945413 but exactly the same solution with map instead of unordered_map 37989920 I have passed. This is not an error because unordered_map faster map, right?

UPD: I just translated to Eng

UPD1:

Everything about unordered_map:

https://codeforces.com/blog/entry/62393

https://codeforces.com/blog/entry/21853

 
 
 
 
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2 weeks ago, # |
Rev. 2   Vote: I like it -35 Vote: I do not like it

Why so much dislikes?

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2 weeks ago, # |
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Good amount of discussion on this same topic can be found here. Read all comments.

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2 weeks ago, # |
  Vote: I like it +1 Vote: I do not like it

The worst case time complexity of operation in unordered_map is O(n) rather than the expected O(1),moreover the complexity of unordered_map is amortised O(1) ,whereas for map is O(log n). Similar thing had happened to me earlier.

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    13 days ago, # ^ |
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    In which cases, unordered_map works O(N)? Could tell me about this?

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      13 days ago, # ^ |
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      Sorry,I don't know any specific case as such. But I am sure there are set of test cases which can make them happen everytime as the hash function which unordered_map uses is known ans thus the cases which produces more and more collisions are bound to produce TLE verdict.

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      13 days ago, # ^ |
        Vote: I like it +17 Vote: I do not like it