15 lines
249 B
Crystal
15 lines
249 B
Crystal
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struct Set
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def powerset
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result = Set(typeof(self)).new
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arr = to_a
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(0..size).each do |n|
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arr.each_combination(n, true) do |comb|
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result << comb.to_set
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end
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end
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result
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end
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end
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p [1, 2, 3, 4].to_set.powerset
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