BinarySearch

BinarySearch.swift

import Foundation

func binarySearch(searchArray: [Int],target: Int, lower: Int, upper: Int) -> Int? {
    if lower > upper {
        return nil
    } else {
        var middle = (lower + upper) / 2
        print(middle)
        
        if searchArray[middle]  == target {
            return searchArray[middle]
        } else if target < searchArray[middle] {
            return binarySearch(searchArray: searchArray, target: target, lower: 0 , upper: middle - 1 )
        }
        else if target > searchArray[middle] {
            return binarySearch(searchArray: searchArray, target: target, lower: middle + 1 , upper: upper )
        }
    }
    return nil
}