Running sum of 1D array

Author: rp-code9

Diff for: README.md

@@ -285,6 +285,10 @@ Princeton Algorithms [Part 1](https://www.coursera.org/learn/algorithms-part1/)
 * Randomized set [Problem](https://leetcode.com/explore/interview/card/top-interview-questions-medium/112/design/813/) [C++](problems/others/RandomizedSet.cpp)
 
 ## Leetcode
+### Array
+* Running sum   [Problem](https://leetcode.com/problems/running-sum-of-1d-array/)
+    * using loop, using partial sum, using accumulate [C++](sites/leetcode/RunningSum.cpp)
+
 ### Maths
 * Top K frequent elements     [Problem](https://leetcode.com/explore/interview/card/top-interview-questions-medium/110/sorting-and-searching/799/)
     * Using hashmap and sorting [C++](sites/leetcode/FrequentElements.cpp)

Diff for: sites/leetcode/RunningSum.cpp

@@ -0,0 +1,84 @@
+// Running Sum of 1d Array https://leetcode.com/problems/running-sum-of-1d-array/
+
+#include <iostream>
+#include <vector>
+#include <cstdlib>
+#include <ctime>
+#include <numeric>
+
+void print(std::vector<int>& numbers)
+{
+    for (auto num : numbers) {
+        std::cout << num << " ";
+    }
+}
+
+std::vector<int> getRandomNumbers(int min, int max, int nums)
+{
+    std::srand(static_cast<unsigned>(std::time(nullptr)));
+    std::rand();
+    std::vector<int> numbers(nums);
+
+    for (int i = 1; i <= nums; ++i) {
+        numbers[i - 1] = min + (std::rand() % (max - min + 1));
+    }
+
+    return numbers;
+}
+
+std::vector<int> runningSum1(std::vector<int>& numbers)
+{
+    std::vector<int> rSum(numbers.size());
+    rSum[0] = numbers[0];
+
+    for (int i = 1; i < numbers.size(); i++) {
+        rSum[i] = rSum[i - 1] + numbers[i];
+    }
+
+    return rSum;
+}
+
+std::vector<int> runningSum2(std::vector<int>& numbers)
+{
+    std::vector<int> rSum(numbers.size());
+    std::partial_sum(numbers.begin(), numbers.end(), rSum.begin());
+
+    return rSum;
+}
+
+std::vector<int> runningSum3(std::vector<int>& numbers)
+{
+    std::vector<int> rSum(numbers.size());
+    rSum[0] = numbers[0];
+
+    for (int i = 1; i < numbers.size(); i++) {
+        rSum[i] = std::accumulate(numbers.begin(), numbers.begin() + i + 1, 0);
+    }
+
+    return rSum;
+}
+
+void test(std::vector<int>& numbers)
+{
+    std::cout << "Numbers : ";
+    print(numbers);
+    std::vector<int> rSum1 = runningSum1(numbers);
+    std::cout << "\nRunning sums : \n";
+    std::cout << "Using loop: \t    ";
+    print(rSum1);
+    std::cout << "\nUsing partial sum: ";
+    std::vector<int> rSum2 = runningSum2(numbers);
+    print(rSum2);
+    std::cout << "\nUsing accumulate: ";
+    std::vector<int> rSum3 = runningSum3(numbers);
+    print(rSum3);
+    std::cout << "\n==============================================\n";
+}
+
+int main()
+{
+    std::vector<int> numbers = getRandomNumbers(1, 100, 15);
+    test(numbers);
+
+    return 0;
+}