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62 lines
1.5 KiB
Plaintext
62 lines
1.5 KiB
Plaintext
10 months ago
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app "prime2"
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packages { pf: "https://github.com/roc-lang/basic-cli/releases/download/0.7.1/Icc3xJoIixF3hCcfXrDwLCu4wQHtNdPyoJkEbkgIElA.tar.br" }
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imports [pf.Stdout, pf.Task]
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provides [main] to pf
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main : Task.Task {} I32
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main =
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numStrings =
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primesIn 50_000_000
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|> List.map Num.toStr
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|> Str.joinWith "\n"
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Stdout.line "$(numStrings)"
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primesIn : U64 -> List U64
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primesIn = \n ->
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numbers = List.concat [2] (List.range { start: At 3u64, end: At n, step: 2 })
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primeSieve numbers
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primeSieve : List U64 -> List U64
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primeSieve = \l ->
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when l is
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[] -> []
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[a] -> [a]
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[head, .., tail] if (Num.powInt head 2) > tail -> l
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[head, .. as tail] ->
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filteredList = List.dropIf tail (\e -> Num.isMultipleOf e head)
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List.concat [head] (primeSieve filteredList)
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countPrimesIn : U64 -> Nat
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countPrimesIn = \limit ->
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List.range { start: At 2, end: At limit }
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|> List.countIf \n ->
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if n < 4 then
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Bool.true
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else if Num.isEven n then
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Bool.false
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else
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res =
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List.range { start: At 3, end: At (Num.ceiling (Num.sqrt (Num.toF64 n))), step: 2 }
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|> List.any \a -> Num.isMultipleOf n a
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|> Bool.not
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res
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expect
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(
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countPrimesIn 100000
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|> \expected ->
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dbg expected
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expected
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)
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== (
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List.len (primesIn 100000)
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|> \actual ->
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dbg actual
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actual
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)
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