Add tasks for all the new languages

Task/24-game-Solve/Swift/24-game-solve.swift

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+import Darwin
+import Foundation
+
+var solution = ""
+
+println("24 Game")
+println("Generating 4 digits...")
+
+func randomDigits() -> [Int] {
+  var result = [Int]()
+  for i in 0 ..< 4 {
+    result.append(Int(arc4random_uniform(9)+1))
+  }
+  return result
+}
+
+// Choose 4 digits
+let digits = randomDigits()
+
+print("Make 24 using these digits : ")
+
+for digit in digits {
+  print("\(digit) ")
+}
+println()
+
+// get input from operator
+var input = NSString(data:NSFileHandle.fileHandleWithStandardInput().availableData, encoding:NSUTF8StringEncoding)!
+
+var enteredDigits = [Double]()
+
+var enteredOperations = [Character]()
+
+let inputString = input as String
+
+// store input in the appropriate table
+for character in inputString {
+  switch character {
+  case "1", "2", "3", "4", "5", "6", "7", "8", "9":
+    let digit = String(character)
+    enteredDigits.append(Double(digit.toInt()!))
+  case "+", "-", "*", "/":
+    enteredOperations.append(character)
+  case "\n":
+    println()
+  default:
+    println("Invalid expression")
+  }
+}
+
+// check value of expression provided by the operator
+var value = 0.0
+
+if enteredDigits.count == 4 && enteredOperations.count == 3 {
+  value = enteredDigits[0]
+  for (i, operation) in enumerate(enteredOperations) {
+    switch operation {
+    case "+":
+      value = value + enteredDigits[i+1]
+    case "-":
+      value = value - enteredDigits[i+1]
+    case "*":
+      value = value * enteredDigits[i+1]
+    case "/":
+      value = value / enteredDigits[i+1]
+    default:
+      println("This message should never happen!")
+    }
+  }
+}
+
+func evaluate(dPerm: [Double], oPerm: [String]) -> Bool {
+  var value = 0.0
+
+  if dPerm.count == 4 && oPerm.count == 3 {
+    value = dPerm[0]
+    for (i, operation) in enumerate(oPerm) {
+      switch operation {
+      case "+":
+        value = value + dPerm[i+1]
+      case "-":
+        value = value - dPerm[i+1]
+      case "*":
+        value = value * dPerm[i+1]
+      case "/":
+        value = value / dPerm[i+1]
+      default:
+        println("This message should never happen!")
+      }
+    }
+  }
+  return (abs(24 - value) < 0.001)
+}
+
+func isSolvable(inout digits: [Double]) -> Bool {
+
+  var result = false
+  var dPerms = [[Double]]()
+  permute(&digits, &dPerms, 0)
+
+  let total = 4 * 4 * 4
+  var oPerms = [[String]]()
+  permuteOperators(&oPerms, 4, total)
+
+
+  for dig in dPerms {
+    for opr in oPerms {
+      var expression = ""
+
+      if evaluate(dig, opr) {
+        for digit in dig {
+          expression += "\(digit)"
+        }
+
+        for oper in opr {
+          expression += oper
+        }
+
+        solution = beautify(expression)
+        result = true
+      }
+    }
+  }
+  return result
+}
+
+func permute(inout lst: [Double], inout res: [[Double]], k: Int) -> Void {
+  for i in k ..< lst.count {
+    swap(&lst[i], &lst[k])
+    permute(&lst, &res, k + 1)
+    swap(&lst[k], &lst[i])
+  }
+  if k == lst.count {
+    res.append(lst)
+  }
+}
+
+// n=4, total=64, npow=16
+func permuteOperators(inout res: [[String]], n: Int, total: Int) -> Void {
+  let posOperations = ["+", "-", "*", "/"]
+  let npow = n * n
+  for i in 0 ..< total {
+    res.append([posOperations[(i / npow)], posOperations[((i % npow) / n)], posOperations[(i % n)]])
+  }
+}
+
+func beautify(infix: String) -> String {
+  let newString = infix as NSString
+
+  var solution = ""
+
+  solution += newString.substringWithRange(NSMakeRange(0, 1))
+  solution += newString.substringWithRange(NSMakeRange(12, 1))
+  solution += newString.substringWithRange(NSMakeRange(3, 1))
+  solution += newString.substringWithRange(NSMakeRange(13, 1))
+  solution += newString.substringWithRange(NSMakeRange(6, 1))
+  solution += newString.substringWithRange(NSMakeRange(14, 1))
+  solution += newString.substringWithRange(NSMakeRange(9, 1))
+
+  return solution
+}
+
+if value != 24 {
+  println("The value of the provided expression is \(value) instead of 24!")
+  if isSolvable(&enteredDigits) {
+    println("A possible solution could have been " + solution)
+  } else {
+    println("Anyway, there was no known solution to this one.")
+  }
+} else {
+  println("Congratulations, you found a solution!")
+}