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49 lines
1.2 KiB
49 lines
1.2 KiB
INSTRUCTIONS = ARGF.read.split("\n")
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def scramble(input)
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INSTRUCTIONS.each do |instruction|
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case instruction
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when /swap position (\d+) with position (\d+)/
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x = $1.to_i
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y = $2.to_i
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input[x], input[y] = input[y], input[x]
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when /swap letter (\w+) with letter (\w+)/
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x = $1
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y = $2
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input.tr!("#{x}#{y}", "#{y}#{x}")
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when /rotate (left|right) (\d+) steps?/
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steps = $2.to_i
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steps = -steps if $1 == 'right'
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input = input.chars.rotate(steps).join
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when /rotate based on position of letter (\w+)/
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index = input.index($1)
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index += 1 if index >= 4
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index += 1
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index = -index
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input = input.chars.rotate(index).join
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when /reverse positions (\d+) through (\d+)/
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x = $1.to_i
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y = $2.to_i
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input[x..y] = input[x..y].reverse
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when /move position (\d+) to position (\d+)/
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x = $1.to_i
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x = input[x]
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input[x] = ''
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y = $2.to_i
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input.insert(y, x)
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else
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raise "invalid instruction: '#{instruction}'"
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end
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end
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input
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end
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input = 'abcdefgh'.chars
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input.permutation.each do |candidate|
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if scramble(candidate.join) == 'fbgdceah'
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puts candidate.join
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exit
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end
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end
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