21 lines
368 B
Ruby
21 lines
368 B
Ruby
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require 'prime'
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def solution
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diagonal_primes = []
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diagonal_composites = []
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increment = 2
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num = 1
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loop do
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4.times do
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num += increment
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if num.prime?
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diagonal_primes << num
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else
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diagonal_composites << num
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end
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return num if (diagonal_primes.count.to_f / diagonal_composites.count.to_f) < 0.1
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end
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end
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end
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