Bounded-Error Log

I’m extremely satisfied — a little incredulous, in fact — with how this puzzle came out. chaotic_iak labels it the “most ridiculous fillomino ever in history”. Apparently, it’s rather tricky.

This is a Fillomino combining the Nonrectangular (polyominoes can’t be rectangles) and Walls (polyominoes can’t span thick lines) variant rules. I think the first variant first came from mathgrant; I’m not as sure about the second, but they both appeared in Fillomino-Fillia 2, at least.

Write a number in every empty cell so that every group of cells with the same number that is connected through its edges is a shape that’s not a rectangle with that number of cells. In addition, cells separated by a thick border may not contain the same number.

I couldn’t remember how long it had been since we entered the ninth floor. Somebody had covered the elevator area with cartoon animals and landscapes. Not surprising, since all the children’s wards were here.

Funny idea, that: I am still a child for medical purposes.

I was not sick. Not more than usually, anyway. I didn’t need to get an IV drip installed or even change into the patient uniform the first night. There was nothing to do or feel. No guilt or fear, unlike last time — this check-up had been scheduled for along time and served as a simple test to see how my bone marrow was doing. No annoyance, either, because I knew it mattered; but no apprehension of the results, or of the needles. You can never get used to the needles, but you learn to just accept them anyway. There is nothing to be done about them.

Who knows? The result could be something bad. But I know enough not to take this hypothetical seriously before it was anything other than hypothetical.

I slept, and dreamt of vomiting carrots.

Oops, I forgot the “puzzles” category was semi-reserved for puzzles I constructed/wrote, because among other things an LMI bot is following it. Anyway, if this makes up for anything, I have a puzzle that I’ve procrastinated posting for very, very long.

This is a Fillomino puzzle. Inequality signs in the grid must be satisfied by the two numbers they touch.

Funny, I go on a trip to Penghu followed by a four-day science camp and also get dragged into drawing classes and some sort of movie advising joint, and this is what I decide to blog about.

Since it’s summer, I went back to Rankk and solved stuff. This is lots of fun if you’re good with computers, plus a little math, cryptography, and general puzzling. I’m still stuck on level 8… oh well. Since the levels didn’t seem very indicative of difficulty to me, I decided to do some analysis.

New challenges have been added to Rankk over time, so my metric of difficulty is the number of solvers divided by the time from release to now. Of course this is far from perfect; for example, a challenge’s author doesn’t always seem consistently counted as a solver, problems with lower numbers and problems that will help level up are more likely to get checked out by new rankkers, and so on. But this is just for fun.

Isn’t it weird to suddenly talk about this topic?

I don’t think that I have ever talked about music any more than briefly in passing. It might be confusing to my finger quotes audience, and I worry I’ll seem inconsistent.

Well, a foolish consistency is the hobgoblin of little minds. If you wonder, “I didn’t know that you sang and played the piano, or you liked music in that way — or, at all…” please note that I didn’t know either.

Parts of this (a majority of questions, I hope) are intended as satire. Other parts of this are silliness created to blow off steam from being coerced into spending nine unproductive hours. Still other parts exist simply because I wanted to have equally many questions per test. Also, 256th post w00t. (2019 edit: after the migration, this post count is wildly incorrect, but whatever.)

“Verbal Reasoning”

Directions: The questions in this test are multiple-choice. Each question has four possible choices. Read each question and decide which answer is the best answer. Find the row in your answer sheet that matches the number of the question. In that row, fill in the oval corresponding to the answer you selected.

“I have been told that any encryption becomes safer if the underlying algorithm is maximally obscured, what is most conveniently done by coding it in Haskell.” – rankk

Functional programming is terribly addicting! Partly I think the completely different way of thinking makes it feel like learning programming, and falling in love with it, all over again. Partly there’s this evil sense of satisfaction from using $s (and later <$>s and =<<s and &&&s) to improve readability for initiated Haskellers and worsen it for everybody else. Partly it’s because Learn You a Haskell for Great Good! is such a fun read — there are too many funny bits to list but my favorite so far is when the author analyzes the first verse of Avril Lavigne’s Girlfriend.

Although I think my code in Haskell tends to be more readable than in other languages, code obfuscation in Haskell is almost natural: all you have to do is refactor the wrong function to be “pointfree”, which means that even though it’s a function that takes arguments, you define it without parameters by manipulating and joining a bunch of other functions. Example (plus a few other tiny obfuscations):

isPrime = liftA2 (&&) (liftA2 ($) (all . ((.) (0 /=)) . rem) (flip
    takeWhile [2..] . (flip (.) $ liftA2 (*) id id) . (>=))) ((<) 1)

QQ wordpress why no Haskell highlighting (Editor’s note from 2017: The migration should highlight this now!)

Also, for some reason, you can do this in Haskell:

ghci> let 2 + 2 = 5 in 2 + 2
5

(via Haskell for the Evil Genius)

Okay, but seriously now. I wrote this about my journey to learn functional programming in the programming babble post half a year ago:

The main obstacle I have is that it’s hard to optimize or get asymptotics when computation is expensive (a big problem if you’re trying to learn through Project Euler problems, particularly ones with lots of primes).

So, I somehow managed to get 25 points all by myself in MUMS Puzzle Hunt 2013. Well, I pestered chaotic_iak a little with 3.3 Diagnosus (.html with animated .gif) but we still didn’t recognize all the Pokémon until hint 3, at which point Google sufficed for me.

This is nowhere near the top, but compared to the usual results of whatever AoPS team I form, it’s amazing. By far the best result of AoPS was on CiSRA in 2010 (46th with 58 points), before I discovered puzzle hunts in AoPS; unfortunately due to people getting older and the influx of younger and younger people to the fora, there are less possible teammates each year and they have less time, so here I am by myself. (Also I could have accepted an invitation from a guy in the some-form-of-Elephant team, but I figure if you can win two MUMS hunts in a row you don’t need any more people.)

All in all: Yay!

I survived midterms.

This is a Slitherlink mutant. Draw a loop through adjacent vertices that cannot intersect itself. Each number indicates how many of the four edges around it are drawn. In addition, each pair of colored squares in corresponding positions (e.g. R1C1 and R6C6, R2C8 and R7C3) must have an equal number of edges drawn around them (i.e. if there were numbers placed there, they would be equal).

because my title needs to mean something. (note from the future: before late 2017, when I migrated to Hugo and GitHub Pages, the blog was called “BetaWorldProblems”.)