Labeled while loops for clarity.

Author: kelvinlauKL

3Sum and 4Sum/3Sum.playground/Contents.swift

@@ -32,11 +32,11 @@ func threeSum<T: BidirectionalCollection>(_ collection: T, target: T.Element) ->
   var ret: [[T.Element]] = []
   var l = sorted.startIndex
 
-  while l < sorted.endIndex { defer { sorted.formUniqueIndex(after: &l) }
+  ThreeSum: while l < sorted.endIndex { defer { sorted.formUniqueIndex(after: &l) }
     var m = sorted.index(after: l)
     var r = sorted.index(before: sorted.endIndex)
 
-    while m < r && r < sorted.endIndex { 
+    TwoSum: while m < r && r < sorted.endIndex { 
       let sum = sorted[l] + sorted[m] + sorted[r]
       if sum == target {
         ret.append([sorted[l], sorted[m], sorted[r]])