ACGN's blog

What if tourist goes rainboy mode? (Simulation)
By ACGN, 2 years ago, In English

DISCLAIMER: NO TOURISTS AND RAINBOYS WERE PINGED

Ah yes, two names that most people on Codeforces have heard -- tourist and rainboy, one known as the CP Legend, and one as the user who does everything reverse. Such a great idea to put them together — a hypothetical user with the same ability as tourist, and solves problems the rainboy way.

For those unaware of the "rainboy way", it means solving the problems in reverse order. In particular, if he cannot solve the final problem, he solves no problems in the contest.

Unfortunately, rainboy had not yet reached red, peaking at 2398 rating. How far can this user go? We shall simulate this user through all the contests that tourist and rainboy took part in comparably, which adds up to 60 contests from Codeforces Round 385 (Div. 2) to Codeforces Global Round 19 over a span of 5 years. Drop a guess before reading the rest?

  • he will be unable to reach red
  • he will peak at GM (2400-2599)
  • he will peak at IGM (2600-2999)
  • he will peak at LGM (3000+)

Pre-discussion

In the simulation, I used Codeforces Visualizer to get our expected rating changes. Credits to the website.

One important thing to note is that an AK still stays an AK, but even if he solves one less problem, that could mean a score of 0 for our challenger. If he succeeds in AKing, he would almost certainly get a top 10 finish. Supposing that one starts at a rating of 2200, then a 10th place finish would give at least 200+ delta, and a top 3 finish could easily be 300+ delta.

On the other hand, tourist failing to AK a round would almost certainly lead to a 0 score and a huge negative delta. Assuming that one starts with 2400 rating, how negative the delta is depends on the type of round -- from around 100 for div. 1 rounds to 300 for combined and global rounds. In combined and global rounds, it is often difficult to AK, and such a fall would be easily felt.

All journeys must begin with a good username: how about a touring boy? "touringboy" -- no, "turingboy" to make it more programming style :)

With this set, let the journey/simulation begin, and may we wish turingboy high ratings.

First contest: Codeforces Round 385 (Div. 2)

Fortunately, tourist managed to solve problems A to C in the div. 1 version, and in this scenario, he would be able to AK this Div. 2 contest with ease.

However, the next context demonstrates how dangerous failing to solve a single problem is:

In Good Bye 2016, tourist did not manage to solve problem H. Unfortunately, that means turingboy won't be getting any points, and a rating drop of -173 follows.

Then our turingboy AKs, 4 times in a row.

Note: for Codecraft-17 and Codeforces Round 391 (Div. 1 + Div. 2, combined), tourist/turingboy got a FST.

Will he be able to reach the LGM mark? The answer is shown below!

turingboy's rating trends

Did you get it right? What do you think?

It is undeniable that rainboy is a skilled programmer deserving of LGM range. But tourist is simply different, otherworldly.

Did you like this "simulation"? If you did, please support this blog post to continue this series :)

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  • Vote: I do not like it

Comments Comments (12)
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2 years ago, # |
  Vote: I like it +72 Vote: I do not like it

Just one question, how come you have so much free time to invest and to create this blog XD

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    2 years ago, # ^ |
      Vote: I like it +15 Vote: I do not like it

    I wrote some code to help me out, so it wasn't as painful... Still, advice: spend the 2 hours on practicing CP instead of doing completely random research like me :)

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2 years ago, # |
  Vote: I like it 0 Vote: I do not like it

How about if rainboy goes normal mode?

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    2 years ago, # ^ |
      Vote: I like it +36 Vote: I do not like it

    I would estimate that he would likely be an LGM.

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

      Can we have that simulation next please!

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        2 years ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        The biggest issue is that we generally have no idea how much will rainboy be able to solve when he solves problems in the right order. As we know, tourist AKs a lot of contests, and a key feature of this sim is that AKs remain AKs. On the other hand, there are lots of contests for which rainboy solves no problems, and we have no idea how would he be ranked if he started from the beginning.

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2 years ago, # |
  Vote: I like it +26 Vote: I do not like it

Very cool post. I recommend putting (Simulation) in the title or something, because when I saw the title I thought it was just a low-effort blog posing the question & not actually answering it too. That was a nice surprise once I opened!

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2 years ago, # |
  Vote: I like it 0 Vote: I do not like it

This blog deserves an upvote

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2 years ago, # |
  Vote: I like it +3 Vote: I do not like it

I was super curious about rainboy and wrote a small blog about him. He must be out there smiling at us right now.

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4 months ago, # |
← Rev. 2   Vote: I like it -10 Vote: I do not like it

.

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4 months ago, # |
  Vote: I like it 0 Vote: I do not like it

What if we merge tourist with 'ainboyr'?

Could we start from the second-to-last problem and leave the last problem for last, as is usually done? Would that be better?

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