Swift:

import Foundation

/*

* Complete the 'isPossible' function below.

*

* The function is expected to return a STRING.

* The function accepts following parameters:

* 1. INTEGER a

* 2. INTEGER b

* 3. INTEGER c

* 4. INTEGER d

*/

func isPossible(a: Int, b: Int, c: Int, d: Int) -> String {

// Write your code here

}

let stdout = ProcessInfo.processInfo.environment["OUTPUT_PATH"]!

FileManager.default.createFile(atPath: stdout, contents: nil, attributes: nil)

let fileHandle = FileHandle(forWritingAtPath: stdout)!

guard let a = Int((readLine()?.trimmingCharacters(in: .whitespacesAndNewlines))!)

else { fatalError("Bad input") }

guard let b = Int((readLine()?.trimmingCharacters(in: .whitespacesAndNewlines))!)

else { fatalError("Bad input") }

guard let c = Int((readLine()?.trimmingCharacters(in: .whitespacesAndNewlines))!)

else { fatalError("Bad input") }

guard let d = Int((readLine()?.trimmingCharacters(in: .whitespacesAndNewlines))!)

else { fatalError("Bad input") }

let result = isPossible(a: a, b: b, c: c, d: d)

fileHandle.write(result.data(using: .utf8)!)

fileHandle.write(" ".data(using: .utf8)!)

Consider a pair of integers, (a, b). The following operations can be performed on (a, b) in any order, zero or more times: (a, b) = (a + b, b) (a, b) (a, a + b) Return a string that denotes whether or not (a, b) can be converted to to (c, d) by by performing zero or more of the operations specified above