advent-of-code/2021/nim/day11.nim

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Nim
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import ./common, std/[sequtils, algorithm, sugar, sets, strformat, strutils]
proc toGrid(s: seq[string]): seq[seq[int]] =
for l in s: result.add(l.mapIt(int(it)-int('0')))
proc octopi(input: seq[seq[int]]): int =
var o = input
let h = o.len
let w = o[0].len
# echo &"w{w} h{h}"
for n in 1..100:
# for nums in o:
# echo nums.mapIt($it).join()
# echo n
var allFlashes = toHashSet[(int, int)] []
var flashes = toHashSet[(int, int)] []
for y in 0..<h:
for x in 0..<w:
# inc and check flashes
inc o[y][x]
if o[y][x] > 9:
# echo &"Flash {y}, {x}"
inc result
flashes.incl (y, x)
allFlashes.incl (y, x)
while flashes.len > 0:
let (y, x) = flashes.pop
# echo &"Handling flash {y}, {x}"
for p in product @[@[y-1, y, y+1], @[x-1, x, x+1]]:
let (fy, fx) = (p[0], p[1])
if fx < 0 or fy < 0 or fx >= w or fy >= h or (fx == x and fy == y): continue
# inc and check flashes
inc o[fy][fx]
if o[fy][fx] > 9 and not allFlashes.contains (fy, fx):
# echo &"Subflash {fy}, {fx}"
inc result
flashes.incl (fy, fx)
allFlashes.incl (fy, fx)
for f in allFlashes.items():
o[f[0]][f[1]] = 0
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proc octopiUntilAll(input: seq[seq[int]]): int =
var o = input
let h = o.len
let w = o[0].len
# echo &"w{w} h{h}"
for n in 1..1000000:
# for nums in o:
# echo nums.mapIt($it).join()
# echo n
var allFlashes = toHashSet[(int, int)] []
var flashes = toHashSet[(int, int)] []
for y in 0..<h:
for x in 0..<w:
# inc and check flashes
inc o[y][x]
if o[y][x] > 9:
# echo &"Flash {y}, {x}"
inc result
flashes.incl (y, x)
allFlashes.incl (y, x)
while flashes.len > 0:
let (y, x) = flashes.pop
# echo &"Handling flash {y}, {x}"
for p in product @[@[y-1, y, y+1], @[x-1, x, x+1]]:
let (fy, fx) = (p[0], p[1])
if fx < 0 or fy < 0 or fx >= w or fy >= h or (fx == x and fy == y): continue
# inc and check flashes
inc o[fy][fx]
if o[fy][fx] > 9 and not allFlashes.contains (fy, fx):
# echo &"Subflash {fy}, {fx}"
inc result
flashes.incl (fy, fx)
allFlashes.incl (fy, fx)
if allFlashes.len() == (w * h):
return n
for f in allFlashes.items():
o[f[0]][f[1]] = 0
doDay 11, n => n.loadInput().toGrid(), octopi, octopiUntilAll,
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@[
"5483143223",
"2745854711",
"5264556173",
"6141336146",
"6357385478",
"4167524645",
"2176841721",
"6882881134",
"4846848554",
"5283751526",
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].toGrid(), 1656, 195