Internet reactions to that sorting algorithm
Well, people talked about the algorithm... though maybe not in the way I
was expecting. Here I will first show you a few places where it is talked
about most (and therefore contain many responses from those who understood
it, but also a lot more from those who didn't). Then in the next few sections
I will highlight a few from those who (1) understood what it is
outright and liked it, (2) took them a while, and (3) didn't see what it
is and said something frankly quite stupid.
Most popular coverage
-
Hacker News:
maybe the place that first broke the news. You will find all kinds of
discussions ranging from someone
immediately mistaking it as exchange sort and claiming that it
(exchange sort) was their invention; to someone
claiming they used it as the first sorting algorithm to introduce sorting
to students (yeah sure...); to someone
saying the algorithm has a "perverse beauty"; to multiple people
arguing the paper should have been a blog post instead; etc.
-
This youtube video gives a nice animation (better than most of the other
animations out there that are either not very clear or even showing the
wrong algorithm like exchange sort), and also an explanation on it being
a combination of insertion sort and selection sort, similar to
what I wrote here. It also describes the
algorithm as "simplest (for a sufficiently perverse definition of the word
simple)". I'll take that as a compliment.
-
Among tweets about the algorithm, this is probably the one with the most
reactions. The OP did not say what they think about it at all, but you
can check the numerous (good and bad) responses. Perhaps not too
surprisingly, I find that generally replies are more likely to be from people
who dismissed it without knowing what it really is, and quoted tweets are
more likely to come from those who understood and liked it.
Some other select tweets
For those who still haven't understood and still mocking the algorithm,
you may want to see what others say...
-
This computer scientist describes it as "beautiful"
and that "What I find beautiful here is that such a combination of short,
concise, counter-intuitive and **correct** exists."
-
This one gives a perfect description: a "programming optical illusion".
-
If you are still fully confident that you got it right and everyone else is dumb,
see more examples of what others said:
Academic communities
-
The algorithm seems to be of interest to the formal verification /
automated theorem proving community. In addition to fooling humans, the
algorithm also seems to trip up many simple theorem proving attempts.
For example the following blog post talks about their (difficult)
experience of proving it with SPARK:
I can't believe that I can prove that it can sort
(Thanks, at last someone play along with the name of the algorithm!)
They are also one of the many people who claimed they discovered the same
algorithm back in their school days... well we only have their word
for that.
-
Someone
proved its correctness in Coq.
I was told privately this was
used as a project in a formal verification course at Google, and that
"it's proving to be an excellent étude for proof by induction".
-
It was used as a case study in a
ESOP 2025 paper about program verification.
-
Some
Taiwan facebook groups about algorithms
reported it, and compared it to the
"Floyd-Warshall wrong loop order doesn't matter if you repeat it 3 times"
paper.
Used in teaching
Some more examples of...
Those who understood it first time round...
To be added
Those who took a while...
To be added
And those who didn't.
To be added