Subarray Division 1.swift

import Foundation

/*
 * Complete the 'birthday' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts following parameters:
 *  1. INTEGER_ARRAY s
 *  2. INTEGER d
 *  3. INTEGER m
 */

func birthday(s: [Int], d: Int, m: Int) -> Int {
    var count = 0
    for index in 0...s.count - m {
        if s[index..<index+m].reduce(0, +) == d { count += 1 }
    }
    return count
}

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

let s: [Int] = sTemp.split(separator: " ").map {
    if let sItem = Int($0) {
        return sItem
    } else { fatalError("Bad input") }
}

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

guard let firstMultipleInputTemp = readLine()?.replacingOccurrences(of: "\\s+$", with: "", options: .regularExpression) else { fatalError("Bad input") }
let firstMultipleInput = firstMultipleInputTemp.split(separator: " ").map{ String($0) }

guard let d = Int(firstMultipleInput[0])
else { fatalError("Bad input") }

guard let m = Int(firstMultipleInput[1])
else { fatalError("Bad input") }

let result = birthday(s: s, d: d, m: m)

fileHandle.write(String(result).data(using: .utf8)!)
fileHandle.write("\n".data(using: .utf8)!)