23 lines
510 B
Ruby
23 lines
510 B
Ruby
def pandigital?(n)
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n.to_s.split('').map(&:to_i).sort == [1,2,3,4,5,6,7,8,9]
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end
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def largest_pandigital_composition_up_to(n)
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largest_pandigital = 1
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(2..n).each do |i|
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digit_list = []
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multiplier = 1
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until digit_list.length >= 9
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digit_list += (i * multiplier).to_s.split('').map(&:to_i)
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multiplier += 1
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end
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number = digit_list.join('').to_i
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if pandigital?(number)
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largest_pandigital = number if number > largest_pandigital
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end
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end
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largest_pandigital
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end
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