85 lines
1.5 KiB
Ruby
85 lines
1.5 KiB
Ruby
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#!/usr/bin/env ruby
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result = File.readlines("2.input").map(&:split).map { _1.map(&:to_i) }
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.select do |v|
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(v == v.sort || v == v.sort.reverse) &&
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v.each_cons(2).map { _1.sort.inject(:-).abs }.all? { 1 <= _1 && _1 <= 3 }
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end.size
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puts result
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require "rspec/autorun"
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class Report < Array
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def self.from_line(line)
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new(line.split.map(&:to_i))
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end
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def safe?
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(increasing? || decreasing?) && within_limit?
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end
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def safe_with_dampener?
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dampened.any?(&:safe?)
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end
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private
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def dampened
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size.times.map { Report.new(except(_1)) }
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end
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def except(v)
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reject.with_index { |_, i| i == v }
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end
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def increasing?
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self == sort
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end
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def decreasing?
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self == sort.reverse
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end
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def within_limit?
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each_cons(2)
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.map { _1.sort.inject(:-).abs }
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.all? { 1 <= _1 && _1 <= 3 }
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end
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end
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input = File.readlines("2.input")
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puts "2-1"
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puts input
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.map { Report.from_line(_1) }
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.select(&:safe?)
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.size
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puts "2-2"
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puts input
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.map { Report.from_line(_1) }
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.select(&:safe_with_dampener?)
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.size
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describe Report do
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[
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"48 51 52 53 52",
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"86 87 88 91 91",
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"22 25 28 31 32 36",
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"65 66 68 69 71 72 75 82"
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].each do |line|
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it "returns safe? as false for #{line}" do
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expect(Report.from_line(line).safe?).to eq(false)
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end
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end
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[
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"1 2 3 4 5 6 7",
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"1 3 5 7 9",
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"9 8 7",
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"1 4 5 8"
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].each do |line|
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it "returns safe? as true for #{line}" do
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expect(Report.from_line(line).safe?).to eq(true)
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end
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end
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end
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