394. Decode String

Author: a-khakimov

leetcode-scala/src/main/scala/LeetCode75/Stack/394. Decode String.sc

@@ -0,0 +1,28 @@
+object Solution {
+  def decodeString(s: String): String = {
+    val stack = scala.collection.mutable.Stack.empty[String]
+    for (c <- s) {
+      if (c != ']') {
+        stack.push(c.toString)
+      } else {
+        var s = ""
+        while (stack.top != "[") {
+          s += stack.pop()
+        }
+        stack.pop()
+        var n = ""
+        while (stack.nonEmpty && stack.top.toIntOption.nonEmpty) {
+          n = stack.pop() + n
+        }
+        stack.push(s * n.toInt)
+      }
+    }
+    stack.mkString.reverse
+  }
+}
+
+
+Solution.decodeString("3[a]2[bc]")      // "aaabcbc"
+Solution.decodeString("3[a2[c]]")       // "accaccacc"
+Solution.decodeString("2[abc]3[cd]ef")  // "abcabccdcdcdef"
+