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54 lines
1.1 KiB
54 lines
1.1 KiB
input = ARGF.read.split("\n")
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class IllegalCharacter < StandardError
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attr_reader :char
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def initialize(char)
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@char = char
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end
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end
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COMPLEMENTS = %w[ () [] {} <> ].map(&:chars).to_h
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OPENING_REGEXP = Regexp.new("[#{Regexp.escape(COMPLEMENTS.keys.join)}]")
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CLOSING_REGEXP = Regexp.new("[#{Regexp.escape(COMPLEMENTS.values.join)}]")
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def parse(line)
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stack = []
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s = line.chars
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until s.empty?
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case char = s.shift
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when OPENING_REGEXP
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stack << char
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when CLOSING_REGEXP
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raise IllegalCharacter.new(char) unless stack.pop == COMPLEMENTS.invert.fetch(char)
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end
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end
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stack
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end
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# points = {
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# ?) => 3,
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# ?] => 57,
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# ?} => 1197,
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# ?> => 25137,
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# }
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# p input.sum {|line|
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# begin
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# parse(line)
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# 0
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# rescue IllegalCharacter => e
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# points.fetch(e.char)
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# end
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# }
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def score(closing) = closing
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.map { COMPLEMENTS.values.index(_1) + 1 }
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.inject(0) {|n,i| n*5 + i }
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scores = input
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.filter_map { parse(_1) rescue nil }
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.map {|remaining| remaining.reverse.map { COMPLEMENTS.fetch(_1) }}
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.map { score(_1) }
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p scores.sort.fetch(scores.length / 2)
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