Create 0682-baseball-game.kt

Author: a93a

kotlin/0682-baseball-game.kt

@@ -0,0 +1,32 @@
+/*
+* Using a stack. Time Complexity O(N) and Space Complexity O(N)
+*/
+class Solution {
+    fun calPoints(operations: Array<String>): Int {
+
+        val stack = ArrayDeque<Int>()
+
+        for(op in operations) {
+            when (op) {
+                "+" -> {
+                    val top = stack.removeLast()
+                    val sum = stack.peekLast() + top
+                    stack.addLast(top)
+                    stack.addLast(sum)
+                }
+                "D" -> {
+                    val top = stack.peekLast() * 2
+                    stack.addLast(top)
+                }
+                "C" -> {
+                    stack.removeLast()
+                }
+                else -> {
+                    stack.addLast(op.toInt())
+                }
+            }
+        }
+
+        return stack.sum()
+    }
+}