Power set: Difference between revisions
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let subsets xs = List.foldBack (fun x rest -> rest @ List.map (fun ys -> x::ys) rest) xs [[]] |
let subsets xs = List.foldBack (fun x rest -> rest @ List.map (fun ys -> x::ys) rest) xs [[]] |
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</lang> |
</lang> |
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alternatively with list comprehension |
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<lang fsharp> |
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let rec pow = |
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function |
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| [] -> [[]] |
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| x::xs -> [for i in pow xs do yield! [i;x::i]] |
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</lang> |
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=={{header|Factor}}== |
=={{header|Factor}}== |
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We use hash sets, denoted by <code>HS{ }</code> brackets, for our sets. <code>members</code> converts from a set to a sequence, and <code><hash-set></code> converts back. |
We use hash sets, denoted by <code>HS{ }</code> brackets, for our sets. <code>members</code> converts from a set to a sequence, and <code><hash-set></code> converts back. |
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