Counting Sort 1.swift

import Foundation

/*
 * Complete the 'countingSort' function below.
 *
 * The function is expected to return an INTEGER_ARRAY.
 * The function accepts INTEGER_ARRAY arr as parameter.
 */

func countingSort(arr: [Int]) -> [Int] {
    var array: [Int] = Array(repeating: 0, count: 100)
    arr.forEach {
        array[$0] += 1
    }

    return array
}

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 arrTemp = readLine()?.replacingOccurrences(of: "\\s+$", with: "", options: .regularExpression) else { fatalError("Bad input") }

let arr: [Int] = arrTemp.split(separator: " ").map {
    if let arrItem = Int($0) {
        return arrItem
    } else { fatalError("Bad input") }
}

guard arr.count == n else { fatalError("Bad input") }

let result = countingSort(arr: arr)

fileHandle.write(result.map{ String($0) }.joined(separator: " ").data(using: .utf8)!)
fileHandle.write("\n".data(using: .utf8)!)