36 lines
1.1 KiB
Swift
36 lines
1.1 KiB
Swift
// MathUtils.swift
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// Mathematical utility functions
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// Corresponds to MathUtils.kt in Android implementation
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import Foundation
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public class MathUtils {
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private static let _fibonacciArray: [Int] = [
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1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946,
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17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578,
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5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155, 165580141, 267914296,
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433494437, 701408733, 1134903170, 1836311903, 2971215073
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]
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public static func fibonacci(_ n: Int, offset: Int = 0) -> Int64 {
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let len = _fibonacciArray.count
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let idx = n + offset
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if idx < len {
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return Int64(_fibonacciArray[idx])
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}
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var n1 = Int64(_fibonacciArray[len - 2])
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var n2 = Int64(_fibonacciArray[len - 1])
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var sum: Int64 = 0
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for _ in len..<idx {
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sum = n1 + n2
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n1 = n2
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n2 = sum
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}
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return sum
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}
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}
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