maroonrk's blog

AtCoder Regular Contest 175 Announcement
By maroonrk, history, 9 months ago, In English

We will hold AtCoder Regular Contest 175.

The point values will be 400-400-600-700-800-1000.

We are looking forward to your participation!

  • Vote: I like it
  • +70
  • Vote: I do not like it

»
9 months ago, # |
  Vote: I like it +13 Vote: I do not like it

overlaps with EUC mirror :(

→ Reply
  • »
    »
    9 months ago, # ^ |
      Vote: I like it +40 Vote: I do not like it

    Have you ever seen in history atcoder changing their contest time for other contests? Never.Great/bad (that judgement is upto you) thing about atcoder is it never compromises its' own contest times for other contests

    → Reply
»
9 months ago, # |
← Rev. 3   Vote: I like it -30 Vote: I do not like it

Have a guess!

Good contest :

Bad contest :

→ Reply
»
9 months ago, # |
  Vote: I like it +30 Vote: I do not like it

How can you solve these HARD problems so FAST? negative again:(

→ Reply
»
9 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Could not code C in time :(

→ Reply
  • »
    »
    9 months ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    The code of C is actually very short.

    Code
    → Reply
    • »
      »
      »
      9 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Interesting, could you explain it? I also needed like 80+ lines :(

      → Reply
»
9 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Finally broke the streak of rk145 and got rk149... Anyway, good contest.

→ Reply
»
9 months ago, # |
  Vote: I like it +15 Vote: I do not like it

I guess the authors like constructive problems veeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeery much!!!

→ Reply
»
9 months ago, # |
  Vote: I like it 0 Vote: I do not like it

This was a bit harder than the other recent arc for me.

→ Reply
  • »
    »
    9 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    a bit?

    → Reply
  • »
    »
    9 months ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Tbh ARC has very bad difficulty distribution many times because problems from C become interesting exclusively to IM+ levels, while A and B can rb solved by Specialist and below. I find all these problems very educational nonetheless but the difficulty curve is not the most optimal. I personally see no reason for ARC to be rated below 1800-1900 simply because it turns into speedforces a lot of times.

    If last ARC had today's C as a D, it would have been an example of a well-balanced ARC.

    → Reply
    • »
      »
      »
      9 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Yes, maybe B and E harder as ARC173B and this contest's E?

      → Reply
      • »
        »
        »
        »
        9 months ago, # ^ |
          Vote: I like it -16 Vote: I do not like it

        Anything other than what we got yesterday would be great. If only problems from C were present yesterday you'd see a well distributed leaderboard, this way 80% of competition shared A and B and time was a tiebreaker.

        → Reply
        • »
          »
          »
          »
          »
          9 months ago, # ^ |
            Vote: I like it 0 Vote: I do not like it

          if you have people who can only solve 0/1/2 problems, naturally its always going to be speedforces for them regardless of the balancing.

          What you are suggesting is making arc easier so that its speedforces on 3 problems for you instead of 2. That isnt enjoyable for the actual audience between 2000 and 2800 rating imo. Last contest had perfect A, C and D level for me (tho CD swap personally). B was a bit too easy but fine.

          The only flaw in the last contest difficulty wise imo is the DE gap.

          → Reply
          • »
            »
            »
            »
            »
            »
            9 months ago, # ^ |
              Vote: I like it 0 Vote: I do not like it

            No, I am not suggesting it be easier for me. I am saying remove A and B completely, as it's really not interesting seeing two 1000 rated problems.

            In an ideal scenario I'd like to see a 1000-1400-1800-2200-2600-3100 distribution. This leaves everyone satisfied. Ofc it is not possible for an author to predict this.

            How was difficulty good when it appears if you solved A you were pretty much guaranteed B, and if you solved C you were guaranteed D, yet both B-C and D-E jumps were hugeee???

            ARC 174 had miles better difficulty distribution for A-C, but D messed it up as well. Either C or D did not belong there.

            And how is it speedforces for me exactly if C is 1700-1800??? It's a literal filler problem between 1000 and 2100.

            All ARC have interesting problems for people in 2100-3000 CF yet there's not a single problem that is not completely trivial but somewhat challenging for the lower rated participants. It's either completely trivial uninteresting shit problems like B and A yesterday, or untouchable like C yesterday.

            What's the point of having it be rated for people at 1500-1700 rating when you know you'll gain 60 points if you are fast and lose 60 if you're slow? You cannot differentiate between a AtCpder green and an AtCoder blue rating, yet in ABC one beats the other by 3000-7000 places.

            → Reply
»
9 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Is there anyone who would like to share your ideas about problem C? Thank you so much.

→ Reply
»
9 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I feel there's a mistake in the editorial for C. In proposition 1.3, the part where the value $$$f_k(x)$$$ is broken down into 3 cases, $$$x<l_k$$$, $$$x>r_k$$$ and $$$x \in [l_k,r_k]$$$, shouldn't it be $$$l_{k+1}$$$ and $$$r_{k+1}$$$ instead of $$$l_k$$$ and $$$r_k$$$?

→ Reply
»
8 months ago, # |
  Vote: I like it 0 Vote: I do not like it

In problem A sample testcase 2 "RlR" satisfies the requirements right?

→ Reply