18 lines
281 B
Ruby
18 lines
281 B
Ruby
# frozen_string_literal: true
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input = File.readlines('./input').map(&:to_i).sort
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$d = { 1 => 0, 2 => 0, 3 => 0 }
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$j = 0
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input << input.max + 3
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input.each do |adapter|
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diff = adapter - $j
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if diff.between? 1, 3
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$d[diff] += 1
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$j = adapter
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end
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end
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puts $d[1] * $d[3]
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