24 lines
453 B
Ruby
24 lines
453 B
Ruby
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def collatz(num)
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list = []
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current_num = num
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while current_num > 1
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list << current_num
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if current_num % 2 == 0
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current_num /= 2
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else
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current_num = 3*current_num + 1
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end
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end
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list << 1
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end
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def longest_chain(num)
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chain_length = {}
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(1..num).each do |starting_num|
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chain_length[starting_num] = collatz(starting_num).count
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end
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chain_length.sort_by { |key, value| value }.last
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end
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puts longest_chain(999999)
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