41 lines
837 B
Swift
41 lines
837 B
Swift
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import Foundation
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func get_primes7(_ n: Int) -> [Int] {
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if n < 2 {
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return []
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} else if n == 2 {
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return [2]
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}
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// do only odd numbers starting at 3
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var s = Array(stride(from: 3, to: n, by: 2))
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let mroot: Int = Int(sqrt(Double(n)))
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let half = s.count
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var i = 0
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var m = 3
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while m <= mroot {
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if s[i] != 0 {
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for j in stride(from: (m*m - 3) / 2, to: half, by: m) {
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s[j] = 0
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}
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}
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i += 1
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m += 2
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}
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return [2] + s.filter { $0 != 0 }
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}
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if let period_time_var = ProcessInfo.processInfo.environment["RUN_TIME"] {
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let start_time = Date()
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let period_time = Int(period_time_var)!
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while Int(Date().timeIntervalSince(start_time)) < period_time {
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let res = get_primes7(10_000_000)
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print("Found \(res.count) prime numbers.")
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}
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} else {
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print("RUN_TIME not found.")
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}
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