Design Minstack 2

Author: TonyStark-19

Stack/DesignMinStack2.cpp

@@ -0,0 +1,78 @@
+#include <iostream>
+#include <stack>
+#include <vector>
+using namespace std;
+// more optimized approach
+
+class MinStack
+{
+public:
+    stack<long long int> s; // val , minVal
+    long long int minVal;
+
+    MinStack() {} // default constructor
+
+    void push(int val)
+    {
+        if (s.empty())
+        {
+            s.push(val);
+            minVal = val;
+        }
+        else
+        {
+            if (val < minVal)
+            {
+                s.push((long long)2 * val - minVal);
+                minVal = val;
+            }
+            else
+            {
+                s.push(val);
+            }
+        }
+    }
+
+    void pop()
+    {
+        if (s.top() < minVal)
+        {
+            minVal = 2 * minVal - s.top();
+        }
+
+        s.pop();
+    }
+
+    int top()
+    {
+        if (s.top() < minVal)
+        {
+            return minVal;
+        }
+
+        return s.top();
+    }
+
+    int getMin()
+    {
+        return minVal;
+    }
+};
+
+int main()
+{
+    MinStack ms;
+
+    ms.push(-2);
+    ms.push(0);
+    ms.push(-3);
+
+    cout << "Minimum value : " << ms.getMin() << endl;
+
+    ms.pop();
+
+    cout << "Top value : " << ms.top() << endl;
+    cout << "Minimum value : " << ms.getMin() << endl;
+
+    return 0;
+}