errorgorn's blog

What were your Favourite Problems/Blogs of 2022?
By errorgorn, 21 month(s) ago, In English

Now that Goodbye 2022 has recently concluded (I hope you liked it). Let's share the best problems from 2022 instead of only before 3 weeks ago (I am looking at you kozliklekarsky).

Btw, I have noticed a trend in these blog posts where many problems come from the last few months of the year. So I hope that we take a good look through the contests of 2022 before posting.

Also, I think it would be a good idea to share your favourite blogs of 2022 as well in case we missed out some genius blog!

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21 month(s) ago, # |
  Vote: I like it +20 Vote: I do not like it

Thank you for rendering my blog useless. I thought we were friends.

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    21 month(s) ago, # ^ |
    ← Rev. 2   Vote: I like it +230 Vote: I do not like it

    Posting "Problem of the Year" 3 weeks before 2022 ends is stupid. Instead, you should have posted it in January 2022.

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      21 month(s) ago, # ^ |
      ← Rev. 3   Vote: I like it -64 Vote: I do not like it

      Bine antontrygubO_o. Se da un sir de cifre separate prin operatori '*', '+', '-', '/', '^', '&', 'XOR', '!' '|'. Avand voie sa faci maxim K interschimbari intre operatori, aflati valoarea maxima a expresiei. Marinush. Posting "Spotify Wrapped" 4 weeks (PATRU!!) before 2022 ends is stupid. Instead, you should've posted it in January 2012.

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        21 month(s) ago, # ^ |
          Vote: I like it -23 Vote: I do not like it

        Elementar. Rezolvarea problemei necesita cunostinte despre evaluarea unei expresii aritmetice, programare dinamica.

        Pentru rezolvarea problemei in cazul general vom nota cu a[1],a[2],...,a[m] operanzii expresiei si cu op[1],op[2],...,op[m − 1] operatorii expresiei, unde m = [N /2] + 1.De asemenea, notam cu d[i][j][h] valoarea maxima a expresiei, ce se obtine utilizand operanzii a[1],a[2],...,a[i], expresie in care s-au folosit j operatori diferiti fata de cei corespunzatori din expresia initiala, si h operatori de inmultire. Desigur, Valoarea lui d[i][j][h] se calculeaza dinamic (cu programari dinamice)

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21 month(s) ago, # |
← Rev. 2   Vote: I like it +19 Vote: I do not like it

tibinyte always pushes his problems

I won't this time, my favorite problem this year was: Calorifer who am I kidding, of course it's Majority!

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21 month(s) ago, # |
  Vote: I like it +6 Vote: I do not like it

problem

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21 month(s) ago, # |
← Rev. 2   Vote: I like it -30 Vote: I do not like it

You know what? Let me just write a blog about calculating the diameter of a polygon using two pointers on the upper and lower hull, and point that blog as my favorite. THIS IS GONNA BE EPIC

UPD: Yes I did

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    21 month(s) ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Brother, errorgorn did nothing wrong, why are you so malicious.

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    21 month(s) ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Are you sure that's correct? I think rotating calipers is cleaner.

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      21 month(s) ago, # ^ |
      ← Rev. 2   Vote: I like it -15 Vote: I do not like it

      I know rotating calipers is one famous way to do it, but trust me, my algorithm is correct (tested with Robert Hood™), and I have proof that the diameter cannot be on the same side of the hull (excluding leftmost/rightmost points). I like the method because I am too stupid to understand Graham scan or Rotating calipers. (Yes, I would have used them if I understood them well enough) I am not really sure about how epic it is though

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21 month(s) ago, # |
  Vote: I like it +34 Vote: I do not like it

Not sure about problems, but I enjoyed reading this blog, even though a lot of it is well-known. It was nice seeing someone finally compile scattered information about hashing into one place.

Spoiler
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21 month(s) ago, # |
  Vote: I like it +44 Vote: I do not like it

1621D - The Winter Hike, 1638D - Big Brush

1704D - Magical Array, 1704E - Count Seconds

1707B - Difference Array, 1710B - Rain, 1718C - Tonya and Burenka-179

1733C - Parity Shuffle Sorting, 1733E - Conveyor <- The author is me, but I thought it is great problem XD.

1746D - Paths on the Tree, 1746E1 - Joking (Easy Version)

1770D - Koxia and Game, 1770E - Koxia and Tree

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21 month(s) ago, # |
  Vote: I like it +7 Vote: I do not like it

1758D - Range = √Sum This problem.

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21 month(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

This problem was a great one.

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21 month(s) ago, # |
← Rev. 4   Vote: I like it +69 Vote: I do not like it

Here are some problems I possibly liked/found interesting this year:

Only problems from the contests I participated/upsolved soon/tested are included in the selection. I didn't participate a lot this year and I believe that lots of good problems aren't here just because of this (or because I accidentally forgot them).

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21 month(s) ago, # |
  Vote: I like it +84 Vote: I do not like it

Spotify, Reddit, Steam and maybe some other things post their yearly summaries in early December too. I don't get it. kozliklekarsky was just following their trend

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21 month(s) ago, # |
  Vote: I like it +40 Vote: I do not like it

1630F - Making It Bipartite

1633F - Perfect Matching

1634F - Fibonacci Additions

1637H - Minimize Inversions Number

1646F - Playing Around the Table

1656E - Equal Tree Sums

1672F2 - Checker for Array Shuffling

1685C - Bring Balance

1687E - Become Big For Me

1689E - ANDfinity

1707E - Replace

1718E - Impressionism

1738G - Anti-Increasing Addicts

1774G - Segment Covering

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21 month(s) ago, # |
← Rev. 2   Vote: I like it +74 Vote: I do not like it

Here's a list of my favourite tasks this year. Thanks to the authors!

  1. Strange Instructions from Hello 2022.
  2. Flights from JOI Spring Camp 2022.
  3. A=B from Moscow Pre-Finals Workshops 2022 Contest 5. (XXII Open Cup, Grand Prix of Yuquan)
  4. Longest Increasing Subsequence from Bytedance-Moscow Workshops 2022 Final Contest. (XXII Open Cup, Grand Prix of Bytedance)
  5. Good Game from Canadian Computing Olympiad 2022.
  6. Flights to the road from Baltic OI 2022.
  7. Triangles from Google Code Jam 2022 World Finals
  8. Imbalance from XXV открытый Чемпионат Урала по спортивному программированию. (XXII Open Cup, Grand Prix of Siberia)
  9. 机器人表演 from UOJ NOI Round #6 Day1.
  10. Partial Virtual Trees from Codeforces Round #808 (Div. 1).
  11. 澡堂 from IOI 2023 China Team Training (CTT 2022).
  12. Happy Game from Xmas Contest 2022.
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21 month(s) ago, # |
  Vote: I like it -21 Vote: I do not like it

I don't know if it's only me but I really enjoy reading blogs about cheaters a lot.

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    21 month(s) ago, # ^ |
      Vote: I like it +19 Vote: I do not like it

    Because you want to know how to write a blog to say you're not a cheater when you've got skipped for the third time? (He's a cheater himself and he's been caught twice).

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      21 month(s) ago, # ^ |
        Vote: I like it -34 Vote: I do not like it

      Well, I had cheated back then (and this is almost 9 months ago when I started CP) because I was very focused on my rating and was afraid of getting negative delta. Later on, I was overwhelmed with guilt and decided never to do it again.

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21 month(s) ago, # |
  Vote: I like it +79 Vote: I do not like it

If you were aware of that previous blog, you could have just commented there.

We will soon have "what is your favorite blog about your favorite problems in 2022"?

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21 month(s) ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

Problem, Nice problem, also Problem2

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21 month(s) ago, # |
  Vote: I like it -8 Vote: I do not like it

My favourite blog is Bakry's blog https://codeforces.me/blog/entry/110245 it is really inspiring.

My 2023 goals are to reach CM hopefully and to do well in my country's National Olympiad.

Happy New Year Every One, Hope you all achieve your Goals.

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21 month(s) ago, # |
  Vote: I like it +46 Vote: I do not like it

some of my favorite tasks in 2022:

From Atcoder:

From Codeforces:

Others:

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21 month(s) ago, # |
← Rev. 2   Vote: I like it +5 Vote: I do not like it

obviously goodbye 2022 C

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21 month(s) ago, # |
← Rev. 6   Vote: I like it +19 Vote: I do not like it

Did not do problems on other OJs as much so this list only mainly contains problems from CF

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Also some problems from atcoder that I recall (wasn't really active on atcoder though)

Others:

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21 month(s) ago, # |
  Vote: I like it +31 Vote: I do not like it

Unfortunately, I don't have any favorite problems in 2022. APIO2022B, AGC059C, IOI2022F deserve some honorable mentions, I think.

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20 months ago, # |
← Rev. 3   Vote: I like it +18 Vote: I do not like it

I think these Codeforces problems were good:

1634F - Fibonacci Additions

1637G - Birthday

1682E - Unordered Swaps

1698F - Equal Reversal

1707F - Bugaboo

1737D - Ela and the Wiring Wizard

1774G - Segment Covering

1770F - Koxia and Sequence

Honorable mention: 1685E - The Ultimate LIS Problem

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