Added C++ code for stack problem Baseball Game (codedecks-in#95)

Author: Shamoyeeta

C++/Baseball-Game.cpp

@@ -0,0 +1,33 @@
+class Solution {
+public:
+    int calPoints(vector<string>& ops) {
+        stack<int> s;
+        auto it=ops.begin();
+        while(it!=ops.end()){
+            if(*it=="+"){    //if char is + then new record is sum of last two records
+                int val1=s.top();
+                s.pop();
+                int val2=s.top();
+                s.push(val1);
+                s.push(val1+val2);
+            }
+            else if(*it=="D"){  //if char is D then new record is twice the last record
+                s.push(2*s.top());
+            }
+            else if(*it=="C"){  //if char is C then the last record is invalidated , hence popped
+                s.pop();
+            }
+            else{  // if none of these conditions occur then just push the new record to stack
+                s.push(stoi(*it));
+            }
+            it++;
+        }
+        int count=0;
+        while(!s.empty())  //iteratively pop the top value of the stack and add it to the total
+        {
+            count+=s.top();
+            s.pop();
+        }
+        return count;
+    }
+};

README.md

@@ -156,7 +156,7 @@ Check out ---> [Sample PR](https://github.com/codedecks-in/LeetCode-Solutions/pu
 | 020 | [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)                               | [Python](./Python/20_ValidParentheses.py)               | _O(n)_ | _O(n)_ | Easy       | Stack |      |
 | 150 | [Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/) | [Python](./Python/150.EvaluateReversePolishNotation.py) | _O(n)_ | _O(1)_ | Medium     | Stack |      |
 | 1047 | [Remove All Adjacent Duplicates In String](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string/) | [C++](./C++/remove-all-adjacent-duplicates-in-string.cpp) | _O(n)_ | _O(n)_ | Easy     | Stack |      |
-
+| 682 | [Baseball Game](https://leetcode.com/problems/baseball-game/) | [C++](./C++/Baseball-Game.cpp) | _O(n)_ | _O(n)_ | Easy     | Stack |      |
 
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