Create baseball-game.cpp

Author: kamyu104

C++/baseball-game.cpp

@@ -0,0 +1,21 @@
+// Time:  O(n)
+// Space: O(n)
+
+class Solution {
+public:
+    int calPoints(vector<string>& ops) {
+        vector<int> records;
+        for (const auto& op : ops) {
+            if (op == "+") {
+                records.emplace_back(records[records.size() - 2] + records.back());
+            } else if (op == "D") {
+                records.emplace_back(2 * records.back());
+            } else if (op == "C") {
+                records.pop_back();
+            } else {
+                records.emplace_back(stoi(op));
+            }
+        }
+        return accumulate(records.begin(), records.end(), 0);
+    }
+};