| 1 | class Bug |
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| 2 | def _isPrime(candidate as int) as bool is shared |
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| 3 | if candidate & 1 == 0 |
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| 4 | return candidate == 2 |
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| 5 | i = 3 |
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| 6 | while i*i <= candidate |
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| 7 | if candidate % i == 0, return false |
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| 8 | i = i + 2 |
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| 9 | return candidate <> 1 |
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| 10 | |
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| 11 | #port of http://labs.kaliko.com/2010/03/cache-functions-in-c-using-memoization.html |
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| 12 | sig Function(param as int) as bool |
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| 13 | |
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| 14 | def memoize(func as Function) as Function |
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| 15 | cache = Dictionary<of int, bool>() |
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| 16 | return do(arg as int) |
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| 17 | result = false |
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| 18 | if cache.containsKey(arg) |
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| 19 | result = cache[arg] |
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| 20 | else |
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| 21 | result = cache[arg] = func(arg) |
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| 22 | return result |
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| 23 | |
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| 24 | |
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| 25 | def _isPrimeFast(candidate as int) as bool is shared |
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| 26 | if candidate & 1 == 0 |
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| 27 | return candidate == 2 |
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| 28 | i = 3 |
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| 29 | while i*i <= candidate |
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| 30 | if candidate % i == 0, return false |
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| 31 | i = i + 2 |
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| 32 | return candidate <> 1 |
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| 33 | |
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| 34 | |
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| 35 | def main |
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| 36 | loops = 10000000 |
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| 37 | sw = System.Diagnostics.Stopwatch() |
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| 38 | sw.start |
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| 39 | #String Builder |
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| 40 | r = List<of bool>() |
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| 41 | for i in loops |
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| 42 | r.add(_isPrime(i)) |
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| 43 | r.clear |
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| 44 | for i in loops |
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| 45 | r.add(_isPrime(i)) |
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| 46 | sw.stop |
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| 47 | GC.collect |
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| 48 | print 'Elapsed Time:[sw.elapsedMilliseconds] ms' |
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| 49 | sw.reset |
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| 50 | sw.start |
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| 51 | isPrime = .memoize<of int,bool>(ref _isPrimeFast) |
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| 52 | sr = List<of bool>() |
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| 53 | for i in loops |
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| 54 | sr.add(isPrime(i) ) |
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| 55 | sr.clear |
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| 56 | for i in loops |
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| 57 | sr.add(isPrime(i) ) |
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| 58 | sw.stop |
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| 59 | print _isPrime(10) |
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| 60 | print _isPrimeFast(10) |
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| 61 | print _isPrime(17) |
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| 62 | print _isPrimeFast(17) |
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| 63 | print _isPrime(1027) |
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| 64 | print _isPrimeFast(1027) |
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| 65 | print _isPrime(1038) |
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| 66 | print _isPrimeFast(1038) |
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| 67 | print sr.count |
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| 68 | print 'Elapsed Time:[sw.elapsedMilliseconds] ms' |
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| 69 | |
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| 70 | return |
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