Codeforces Round #411 Editorial

Revision en16, by saliii, 2017-05-07 15:39:24

We were waiting several weeks to setting this contest and hope the problem was good enough.

Events

There was a difficulty with 805E - Ice cream coloring/804C - Ice cream coloring. A little bug in the checker fortunately yields accepting an incorrect solution of only one person during the contest. I should apologize all of you because of this.

For this sentence, Vertices which have the i-th (1 ≤ i ≤ m) type of ice cream form a connected subgraph. You can find the meaning of "connected subgraph" with connected and subgraph, thus it can be empty as it is more logical. How ever, I should apologize all of the participants because of weak sample tests in the statement.

I will write the full editorial in the few next days, now some hints and short solutions exist here.

Hints

805A - Fake NP

hint1

805B - 3-palindrome

hint1

805C - Find Amir / 804A - Find Amir

hint1
hint2

805D - Minimum number of steps / 804B - Minimum number of steps

hint1
hint2
hint3
hint4

805E - Ice cream coloring / 804C - Ice cream coloring

hint1
hint2
hint3

805F - Expected diameter of a tree / 804D - Expected diameter of a tree

hint1
hint2

804E - The same permutation

hint1
hint2
hint3

804F - Fake bullions

hint1
hint2
hint3
hint4
hint5
hint6

Solutions

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From: Chamran, Writer: Chamran

Time Complexity:

Memory complexity:

python3
C++
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From: Chamran, Writer: Chamran

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python3
C++
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From: Chamran, Writer: Chamran

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python3
C++
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From: MohammadJA, Writer: MohammadJA

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python3
C++
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From: Chamran, Writer: Chamran

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C++

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C++
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From: MohammadJA, Writer: MohammadJA

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C++
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From: Chamran, Writer: Chamran

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C++
Tutorial is loading...

From: Chamran, Writer: Hifdah

Time Complexity:

Memory complexity:

Java8
C++
C++

As my good friend, Arpa, did, let me share with you a perfect poem of one of our best poet you might know, Molavi:

.......................................................................................بند بگسل، باش آزاد ای پسر ** چند باشی بند سیم و بند زر

O son,  burst thy chains and be free! How long wilt thou be a bondsman to silver and gold?

.......................................................................................گر بریزی بحر را در کوزه‌‌ای ** چند گنجد قسمت یک روزه‌‌ای‌‌

If thou pour the sea into a pitcher,  how much will it hold? One day's store.

..................................................................................... کوزه‌‌ی چشم حریصان پر نشد ** تا صدف قانع نشد پر در نشد

The pitcher,  the eye of the covetous,  never becomes full:  the oyster - shell is not filled with pearls until it is contented.

.............................................................................. هر که را جامه ز عشقی چاک شد ** او ز حرص و عیب کلی پاک شد

He (alone) whose garment is rent by a (mighty) love is purged entirely of covetousness and defect.

Tags 411, codeforces round #411, tutorial, tutorials

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en16 English saliii 2017-05-07 15:39:24 704
en15 English saliii 2017-05-06 20:37:54 1217 Tiny change: 'صان \ پر \نشد ** تا' -> 'صان \ پر \ نشد ** تا'
en14 English saliii 2017-05-06 19:59:34 6 Tiny change: '\sqrt(n) \log(n) +' -> '\sqrt(n) \cdot \log(n) +'
en13 English saliii 2017-05-06 19:58:26 53
en12 English saliii 2017-05-06 10:37:39 2978
en11 English saliii 2017-05-06 09:21:22 41 Tiny change: 'al:805D]\n_**To DO...**_\n\nTime C' -> 'al:805D]\n\nTime C'
en10 English saliii 2017-05-05 23:42:40 20699 Tiny change: 'We were wa' -> ' We were wa'
en9 English saliii 2017-05-05 18:11:59 196 (published)
en8 English saliii 2017-05-05 18:05:07 198 Tiny change: ':804A]\n[toturial:805C]' -> ':804A]\n[tutorial:805C]' (saved to drafts)
en7 English saliii 2017-05-05 17:16:48 6 Tiny change: 'e trivial upper-bound s' -> 'e trivial lower-bound s'
en6 English saliii 2017-05-05 16:21:21 6 Tiny change: 'a trivial upper-bound f' -> 'a trivial lower-bound f'
en5 English saliii 2017-05-05 14:40:04 47 Tiny change: 'oiler>\n\n' -> 'oiler>\n\n\nSolutions\n==================\n_**TO DO...**_'
en4 English saliii 2017-05-05 14:38:16 25 Tiny change: 'st here.\n\n[problem' -> 'st here.\nHints\n------------------\n[problem'
en3 English saliii 2017-05-05 14:33:54 38 Tiny change: 'ough.\n### Events' -> 'ough.\n#### Events'
en2 English saliii 2017-05-05 14:33:21 6426 Tiny change: 'tion. So $\choose{2}{n}$\n</spoi' -> 'tion. So $n \choose{}$\n</spoi' (published)
en1 English saliii 2017-05-05 08:33:09 3119 Initial revision (saved to drafts)