Split the States (2021)

[harperlee]

I quite like the chirurgical, strategic feel of the exposition. Denotes clear thinking, and/or multiple revisions.

When I work in some code I often spend too much time on reviewing and enhancing code in this way, but mine being a side project all that work (I’m not the best programmer by far) is either for future me or for no one, and often I end up feeling that I lost time for nothing.

But I like to spend time in making this kind of clean code {shrug}.

[adolph]

chirurgical [ kī-rûr′jĭ-kəl ] adj. Surgical. No longer in technical use.

[biorach]

I've read a lot of code. Peter Norvig's code operates at a different level to anything else I've ever read.

And he's been doing this a long time. I've read part of the way through "Paradigms of Artificial Intelligence Programming" which is from 1991, and uses much the same approach as in the OP, but with Common Lisp.

[nl]

His code is beautiful and his explanations are so clear it makes me feel dumb for not seeing his solutions for myself.

Obviously his approach is the right way. Except they usually aren't obvious until you've read the explanation.

His 22 line spell checker[1] is a perfect example.

[1] https://norvig.com/spell-correct.html

[d_burfoot]

I was really hoping this was a political manifesto, not a programming puzzle

[wwweston]

That kind of dramatic change usually only benefits people with nothing to lose or a distinct next-level gain to make.

Norvig definitely isn't in the first category and has many better avenues for gains than an attempted split of the US (think about who does potentially benefit from that).

Plus hackers love puzzles.

So it's not surprising that politics isn't what it was about.

[karolsputo]

Me too! I was surprised at the title, fully expecting Norvig to channel Michael Malice and talk about splitting the US.

[wodenokoto]

I’m not sure I understand how the `border` variable works.

Sets in Python are really cool when you can master them, but I do sometimes wonder if they are too clever, or just not evangelized enough.

[dec0dedab0de]

when you pipe a set it's the same thing as calling union on each one, it creates a new set and puts all the variables in them:

so this:

  border = north | south | west | east

is the same thing as:

  border = north.union(south, west, east)

which is also:

  border = set()
  for border_set in [north, south, west, east]:
    for state in border_set:
      border.add(state)

it's just a new set with all the previous items in it. Since it's a set there is no doubles. for example, WA is in north and east, but only in border once, because there is no duplicates in a set.

to do it with lists you would need to make sure there was no doubles yourself. plus you wouldn't get the set operations later on, and would need similar loops to check things.

  border = []
  for state in north + south + west + east:
    if state not in border:
      border.append(state)

Sets are great any time you need to work with groups of unique things and see how they relate to each other. Since there is only one of each state, this is perfect use for them.

edits throughout as I thought of other things.

[williamdclt]

If sets were a Python-only thing I'd say that it's too clever, but it's a concept that appears in many other environments: Typescript (unions), Datalog and other declarative logic languages, Haskell (I think) and other functional languages...

So python is implementing an existing paradigm, not trying to be clever inventing something new. I'm happy with that

[onychomys]

The accepted answer from 538 can be found here: https://fivethirtyeight.com/features/can-you-bowl-three-stri...

[anonymous_they]

Not sure if it's just me, but I'm getting really weird rendering bugs when I visit this link.

Maybe GitHub's rendering of ipynb files?

[archi42]

Oh, isn't this a variation of the Knapsack (or more precisely subset sum) problem? With the additional constraint of adjacency.

[charleskinbote]

This reminds me of balanced graph partitioning, where the graph is planar and its the nodes that have weights instead of the edges.

[serverlessmom]

wow nice solution, saw this on 538 and couldn't think of any clever solution.

[jayspell]

Is this just an exercise?

[hirundo]

It's a puzzle:

"Welcome to The Riddler. Every week, I offer up problems related to the things we hold dear around here: math, logic and probability."

[jmclnx]

The image cannot be dispalied. I wish github only allowed Open Image Formats, but too late now since Microsoft owns them.

Lately I have been running into image/video files people at work create on their MACs that cannot be viewed in Linux. I wonder if that crap is carrying ofer into github.

[enobrev]

In this case, it's not a matter of image formats, but simply a 404.

https://github.com/norvig/pytudes/raw/5e745c392772d150b41462...

Here's map4.png: https://github.com/norvig/pytudes/blob/main/ipynb/map4.png

There doesn't seem to be a 5 or 6.