2016 Update

Task/Balanced-brackets/Scala/balanced-brackets-4.scala

@@ -0,0 +1,18 @@
+@scala.annotation.tailrec
+final def isBalanced(
+  str: List[Char],
+  // accumulator|indicator|flag
+  balance: Int = 0,
+  options_Map: Map[Char, Int] = Map(('[' -> 1), (']' -> -1))
+): Boolean = if (balance < 0) {
+  // base case
+  false
+} else {
+  if (str.isEmpty){
+    // base case
+    balance == 0
+  } else {
+    // recursive step
+    isBalanced(str.tail, balance + options_Map(str.head))
+  }
+}