added cpp code for finding sum of areas of rectangle in an array

greedy/sum_areas_rectangle/cpp/program.cpp

@@ -0,0 +1,55 @@
+
+// CPP code to find sum of all 
+// area rectangle possible 
+#include <bits/stdc++.h> 
+using namespace std; 
+
+int MaxTotalRectangleArea(int a[],  
+                          int n) 
+{ 
+    sort(a, a + n, greater<int>()); 
+
+    int sum = 0; 
+    bool flag = false; 
+
+    int len; 
+
+    for (int i = 0; i < n; i++)  
+    { 
+        if ((a[i] == a[i + 1] || a[i] -  
+            a[i + 1] == 1) && (!flag))  
+        { 
+            flag = true; 
+
+            len = a[i + 1]; 
+
+            i++; 
+        } 
+
+        else if ((a[i] == a[i + 1] ||  
+                a[i] - a[i + 1] == 1) && (flag))  
+            { 
+                sum = sum + a[i + 1] * len; 
+
+                flag = false; 
+
+
+                i++; 
+            } 
+    } 
+
+    return sum; 
+} 
+
+// Driver code 
+int main() 
+{ 
+    int a[] = { 10, 10, 10, 10, 
+                11, 10, 11, 10, 
+                9, 9, 8, 8 }; 
+    int n = sizeof(a) / sizeof(a[0]); 
+
+    cout << MaxTotalRectangleArea(a, n); 
+
+    return 0; 
+}