54 lines
1.4 KiB
Plaintext
54 lines
1.4 KiB
Plaintext
import "./math" for Int
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import "./fmt" for Fmt
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var inc = [4, 2, 4, 2, 4, 6, 2, 6]
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// Assumes n is odd.
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var firstPrimeFactor = Fn.new { |n|
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if (n == 1) return 1
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if (n%3 == 0) return 3
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if (n%5 == 0) return 5
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var k = 7
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var i = 0
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while (k * k <= n) {
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if (n%k == 0) {
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return k
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} else {
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k = k + inc[i]
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i = (i + 1) % 8
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}
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}
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return n
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}
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var blum = List.filled(50, 0)
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var bc = 0
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var counts = { 1: 0, 3: 0, 7: 0, 9: 0 }
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var i = 1
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while (true) {
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var p = firstPrimeFactor.call(i)
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if (p % 4 == 3) {
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var q = i / p
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if (q != p && q % 4 == 3 && Int.isPrime(q)) {
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if (bc < 50) blum[bc] = i
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counts[i % 10] = counts[i % 10] + 1
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bc = bc + 1
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if (bc == 50) {
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System.print("First 50 Blum integers:")
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Fmt.tprint("$3d ", blum, 10)
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System.print()
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} else if (bc == 26828 || bc % 1e5 == 0) {
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Fmt.print("The $,9r Blum integer is: $,9d", bc, i)
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if (bc == 400000) {
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System.print("\n\% distribution of the first 400,000 Blum integers:")
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for (i in [1, 3, 7, 9]) {
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Fmt.print(" $6.3f\% end in $d", counts[i]/4000, i)
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}
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return
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}
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}
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}
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}
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i = (i % 5 == 3) ? i + 4 : i + 2
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}
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