[2022][ruby][18.x]

pull/1/head
Alpha Chen 2 years ago
parent da36d561b8
commit ce623e16d1
Signed by: alpha
SSH Key Fingerprint: SHA256:3fOT8fiYQG/aK9ntivV3Bqtg8AYQ7q4nV6ZgihOA20g

@ -0,0 +1,50 @@
cubes = ARGF.read.lines(chomp: true).map { _1.split(?,).map(&:to_i) }
# part one
# p cubes.sum {|cube|
# 6 - cubes.count {|other|
# cube.zip(other).map { _1 - _2 }.map(&:abs).sum == 1
# }
# }
deltas = [
[-1, 0, 0],
[ 1, 0, 0],
[ 0, -1, 0],
[ 0, 1, 0],
[ 0, 0, -1],
[ 0, 0, 1],
]
bounds = cubes.transpose.map(&:minmax).map {|(min, max)| (min-1..max+1) }
cubes = cubes.to_h { [_1, true] }
corners = [
[bounds[0].begin, bounds[1].begin, bounds[2].begin],
[bounds[0].begin, bounds[1].begin, bounds[2].end],
[bounds[0].begin, bounds[1].end, bounds[2].begin],
[bounds[0].begin, bounds[1].end, bounds[2].end],
[bounds[0].end, bounds[1].begin, bounds[2].begin],
[bounds[0].end, bounds[1].begin, bounds[2].end],
[bounds[0].end, bounds[1].end, bounds[2].begin],
[bounds[0].end, bounds[1].end, bounds[2].end],
]
frontier = [corners[0]]
seen = Hash.new
until frontier.empty?
current = frontier.shift
neighbors = deltas.map {|delta| current.zip(delta).map { _1 + _2 }}
.select {|neighbor| bounds.zip(neighbor).all? {|(bound, i)| bound.cover?(i) }}
seen[current] = neighbors.any? { cubes.has_key?(_1) }
frontier.concat(neighbors.reject {|neighbor| seen.has_key?(neighbor) || cubes.has_key?(neighbor) })
frontier.uniq!
end
p cubes.keys.sum {|cube|
neighbors = deltas.map {|delta| cube.zip(delta).map { _1 + _2 }}
neighbors.count { seen.has_key?(_1) }
}
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