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exponent_DivideAndConquer.swift
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exponent_DivideAndConquer.swift
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import Foundation
extension BinaryInteger {
func isOdd() -> Bool{
return self % 2 != 0
}
func isEven() -> Bool{
return self % 2 == 0
}
}
func exponentiate_basic(base: Int, exponent: Int) -> Int {
var result = 1
for _ in 0..<exponent {
result *= base
}
return result
}
func exponentiate_DnQ(base: Int, exponent: Int) -> Int {
if exponent == 0 {
return 1
}else if exponent == 1 {
return base
}else if exponent.isOdd() {
return base * exponentiate_DnQ(base: (base * base), exponent: (exponent-1)/2)
}else if exponent.isEven() {
return exponentiate_DnQ(base: (base * base), exponent: exponent/2)
}
return -1
}
func countTime(_ fn: @autoclosure () -> Any) -> Double {
let startTime = DispatchTime.now()
fn()
let endTime = DispatchTime.now()
let nanoTime = endTime.uptimeNanoseconds - startTime.uptimeNanoseconds
let timeInterval_inSeconds = Double(nanoTime) / 1_000_000_000
return timeInterval_inSeconds
}
countTime(print("Hello"))
countTime(print("Hello"))
countTime(print("Hello"))
countTime(exponentiate_basic(base: 2, exponent: 50))
countTime(exponentiate_DnQ(base:2, exponent:50))