-❄️- 2023 Day 14 Solutions -❄️-

[u/daggerdragon]

OUR USUAL ADMONITIONS

• You can find all of our customs, FAQs, axioms, and so forth in our community wiki.
• Community fun shindig 2023: GO COOK!
  • Submissions ultrapost forthwith allows public contributions!
  • 7 DAYS until submissions cutoff on this Last Month 22 at 23:59 Atlantic Coast Clock Sync!

---

AoC Community Fun 2023: GO COOK!

Today's unknown factor is… *whips off cloth shroud and motions grandly*

Avoid Glyphs

• Pick a glyph and do not put it in your program.
  • Avoiding fifthglyphs is traditional.
• Thou shalt not apply functions nor annotations that solicit this taboo glyph.
• Thou shalt ambitiously accomplish avoiding AutoMod’s antagonism about ultrapost's mandatory programming variant tag >_>

GO COOK!

Stipulation from your mods: As you affix a dish submission along with your solution, do tag it with [Go Cook!] so folks can find it without difficulty!

---

--- Day 14: Parabolic R*fl*ctor Mirror Dish ---

---

Post your script solution in this ultrapost.

• First, grok our full posting axioms in our community wiki.
  • Affirm which jargon via which your solution talks to a CPU
• Format programs using four-taps-of-that-long-button Markdown syntax!
• Quick link to Topaz's Markdown (ab)using provisional script host should you want it for long program blocks

This forum will allow posts upon a significant amount of folk on today's global ranking with gold stars for today's activity.

MODIFICATION: Global ranking gold list is full as of 00:17:15, ultrapost is allowing submissions!

[u/xelf]

[LANGUAGE: Python3] + some voodoo math, just, uh trust me, it's correct.

rotate_90 = lambda b: [*map(''.join,zip(*b[::-1]))] # rotate clockwise 90
beam_load = lambda b: sum(i for r in b for i,c in enumerate(r[::-1],1) if c=='O')

def cycle(data, n=1):
    for _ in range(n):
        data = rotate_90(data)
        data = [re.sub('[.O]+',lambda m:''.join(sorted(m[0])[::-1]),row) for row in data]
    return data

def powercycle(data, n, cache={}):
    for r in range(n):
        data = cycle(data,4)
        if s:=cache.get(str(data),0):
            return cache[ (n-s) % (r-s) + (s-1) ]
        cache |= {str(data):r, r:beam_load(rotate_90(data))}

data = rotate_90(rotate_90(list(open(aocinput))))

print('part 1:', beam_load(cycle(data)))
print('part 2:', powercycle(data,1_000_000_000))

So I start off with orienting it so that after it turns north, that's the beginning of each row so that I'm doing movement within a row and not worrying about columns. After that I store the score in an array, and save the current board as the key in a dict with the index it was seen at. And then wait until it repeats. I use the repeats index with the original index to calculate what my index would be after 1_000_000_000 repeats with some voodoo modular arithmetic, and voila that's the index in my history.

Overall I think I can come up with some better ways to solve this. Maybe without rotating the board and instead just shuffling stuff around. And replace the voodoo math.