Day 1: Quartiles

import Foundation
//Day 1: Quartiles
func medianFunc(numbers: [Int]) -> Double {
    let sortedNumbers = numbers.sorted(by: { num1, num2 in
        return num1 < num2 })
    
    let midIndex = numbers.count / 2
    var median = Double(sortedNumbers[midIndex])
    if(numbers.count % 2 == 0){
        median = Double(sortedNumbers[midIndex] + sortedNumbers[midIndex - 1]) / Double(2)
    }
    
    return median
}

func quartiles(numbers: [Int]) -> [Int] {
    let sortedNumbers = numbers.sorted(by: { num1, num2 in
        return num1 < num2 })
    var midIndex = sortedNumbers.count / 2
    
    var lowerHalf = [Int]()
    for i in 0..<midIndex {
      lowerHalf.append(sortedNumbers[i])
    }
    
    var median = Double(sortedNumbers[midIndex])
    if(sortedNumbers.count % 2 == 0){
        median = Double(sortedNumbers[midIndex] + sortedNumbers[midIndex - 1]) / Double(2)
        midIndex = midIndex - 1
    }
    
    var UpperHalf = [Int]()
    for i in (midIndex+1)..<sortedNumbers.count {
        UpperHalf.append(sortedNumbers[i])
    }
//    print(sortedNumbers)
//    print(UpperHalf)
    
    var result : [Int] = [Int]()
    result.append(Int(medianFunc(numbers: lowerHalf)))
    result.append(Int(median))
    result.append(Int(medianFunc(numbers: UpperHalf)))
    

    return result
}

//quartiles(numbers: [3 ,7, 8, 5, 12, 14, 21, 13, 18])
//quartiles(numbers: [7, 15, 36, 39, 40, 41])
//quartiles(numbers: [3, 7, 8, 5, 12, 14, 21, 15, 18, 14])
//Expected
//7
//13
//15


let stdout = ProcessInfo.processInfo.environment["OUTPUT_PATH"]!
FileManager.default.createFile(atPath: stdout, contents: nil, attributes: nil)
let fileHandle = FileHandle(forWritingAtPath: stdout)!

guard let n = Int((readLine()?.trimmingCharacters(in: .whitespacesAndNewlines))!)
    else { fatalError("Bad input") }

guard let arTemp = readLine() else { fatalError("Bad input") }
let ar: [Int] = arTemp.split(separator: " ").map {
    if let arItem = Int($0.trimmingCharacters(in: .whitespacesAndNewlines)) {
        return arItem
    } else { fatalError("Bad input") }
}


guard ar.count == n else { fatalError("Bad input") }
let resultvalue = quartiles(numbers: ar)

fileHandle.write(String(resultvalue[0]).data(using: .utf8)!)
fileHandle.write("\n".data(using: .utf8)!)
if(resultvalue[1] != 0){
fileHandle.write(String(resultvalue[1]).data(using: .utf8)!)
fileHandle.write("\n".data(using: .utf8)!)

}

fileHandle.write(String(resultvalue[2]).data(using: .utf8)!)
fileHandle.write("\n".data(using: .utf8)!)