fcspartakm's blog

By fcspartakm, 6 years ago, translation, In English
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6 years ago, # |
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    6 years ago, # ^ |
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    Nice!

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    6 years ago, # ^ |
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    I also solve it with maxflow like an assignment problem. 38199894

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    3 years ago, # ^ |
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    What's the time complexity of your solution?

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      3 years ago, # ^ |
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      doesn't matter dude! his sol is over-kill for this problem. just assign days greedily. Whichever exam comes first gets preparation day first.

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6 years ago, # |
  Vote: I like it +5 Vote: I do not like it

Very fast! Thank you

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6 years ago, # |
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Thanks for quick explanation. Is there any solution which works faster than "brute solution" for problem D?

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6 years ago, # |
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For G you don't need to iterate all the exams every day.

38195700 complexity is O(n*logm) insted of O(n*m)

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    4 years ago, # ^ |
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    Excellent thanks for posting

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    2 years ago, # ^ |
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    I might be a little late but can you please explain your logic ?

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6 years ago, # |
Rev. 2   Vote: I like it +4 Vote: I do not like it

A simple way of understanding 978E - Система видеонаблюдения в автобусе:

Define pre[i]  = 

Let's take an arbitrary variable initial which could hold all possible initial values.

It is easy to see this inequality holds true:

0  ≤  initial + pre[i]  ≤  w,

Which implies:

 - pre[i]  ≤  initial  ≤  w - pre[i]

We can reduce this to:

max(0,  - pre[i])  ≤  initial  ≤  min(w, w - pre[i])

Solving this inequality and finding the range gives us the final answer.

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6 years ago, # |
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For F instead of using vectors with quarrels another nice way is to process the quarrels by incrementing an array containing the "number of quarrels with less skilled programmers". Then we can just directly subtract the number in that array at the end.

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6 years ago, # |
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My solution 38166452 to problem 978B - Имя файла was similar to the one in the tutorial, but easiest, it's how many ocurrences have the string "xxx" in the string s.

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6 years ago, # |
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fcspartakm I think there was a typo in the tutorial of problem F: "we can user array of pairs" for "we can use array of pairs".

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6 years ago, # |
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Regexp solution is very easy to write for B :P

print sum(map(lambda x : len(x) - 3 + 1, re.findall('x{3,}', raw_input())))