migrate two sum problem to swift 3

Author: JaapWijnen

Two-Sum Problem/Solution 1/2Sum.playground/Contents.swift

@@ -1,6 +1,6 @@
 //: Playground - noun: a place where people can play
 
-func twoSumProblem(a: [Int], k: Int) -> ((Int, Int))? {
+func twoSumProblem(_ a: [Int], k: Int) -> ((Int, Int))? {
   var map = [Int: Int]()
 
   for i in 0 ..< a.count {

Two-Sum Problem/Solution 1/2Sum.playground/timeline.xctimeline

@@ -1,6 +1,6 @@
 //: Playground - noun: a place where people can play
 
-func twoSumProblem(a: [Int], k: Int) -> ((Int, Int))? {
+func twoSumProblem(_ a: [Int], k: Int) -> ((Int, Int))? {
   var i = 0
   var j = a.count - 1
 
@@ -9,9 +9,9 @@ func twoSumProblem(a: [Int], k: Int) -> ((Int, Int))? {
     if sum == k {
       return (i, j)
     } else if sum < k {
-      ++i
+      i += 1
     } else {
-      --j
+      j -= 1
     }
   }
   return nil