You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
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Report = Data.define(:levels) do
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def safe?
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deltas = levels.each_cons(2).map { _1 - _2 }
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(deltas.all?(&:negative?) || deltas.all?(&:positive?)) && (deltas.all? { (1..3).cover?(_1.abs) })
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end
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def dampened
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return enum_for(__method__) unless block_given?
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(0...levels.length).each do |i|
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yield Report.new(levels[0...i] + levels[i+1..])
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end
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end
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end
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input = DATA.readlines(chomp: true)
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.map { _1.scan(/\d+/).map(&:to_i) }
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.map { Report.new(_1) }
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# part one
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pp input.count(&:safe?)
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# part two
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pp input.count { _1.safe? || _1.dampened.any?(&:safe?) }
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__END__
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7 6 4 2 1
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1 2 7 8 9
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9 7 6 2 1
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1 3 2 4 5
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8 6 4 4 1
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1 3 6 7 9
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