cpp: add “1800. Maximum Ascending Subarray Sum”

Signed-off-by: Matej Focko <me@mfocko.xyz>

cpp/maximum-ascending-subarray-sum.cpp

@@ -0,0 +1,36 @@
+#include <algorithm>
+#include <cassert>
+#include <vector>
+
+class Solution {
+  public:
+    int maxAscendingSum(const std::vector<int> &nums) {
+        if (nums.empty()) {
+            return 0;
+        }
+
+        int found = nums[0];
+        int current = nums[0];
+
+        for (auto i = 1u; i < nums.size(); ++i) {
+            if (nums[i] > nums[i - 1]) {
+                current += nums[i];
+            } else {
+                current = nums[i];
+            }
+            found = std::max(found, current);
+        }
+
+        return found;
+    }
+};
+
+int main() {
+    Solution s;
+
+    assert(s.maxAscendingSum(std::vector{10, 20, 30, 5, 10, 50}) == 65);
+    assert(s.maxAscendingSum(std::vector{10, 20, 30, 40, 50}) == 150);
+    assert(s.maxAscendingSum(std::vector{12, 17, 15, 13, 10, 11, 12}) == 33);
+
+    return 0;
+}