adding leetcode solution

leetcode/p1480_runningsumofarray.cpp

@@ -0,0 +1,23 @@
+class Solution {
+public:
+    vector<int> runningSum(vector<int>& nums) {
+        int sum=0;
+        vector<int> result;
+        int size = nums.size();
+        // because runningSum will have size elements, and runningSum[0] is the sum of one element, i.e., nums[0]. 
+        for(int i=1;i<(size+1);i++){
+            int *a = new int[i];
+            // sum stores the sum from nums[0] to nums[i]
+            for(int j=0;j<i;j++){
+                a[j] = nums[j];
+                sum = sum + a[j];
+            }
+            result.push_back(sum);
+            // allocated memory for an array, and thus delete memory for an array
+            delete [] a;
+            // reset sum so as to reuse it.
+            sum = 0;
+        }
+        return result;
+    }
+};