diff --git a/Makefile b/Makefile
index 45dee95..f00b36d 100644
--- a/Makefile
+++ b/Makefile
@@ -68,11 +68,15 @@ lint/yaml:
 lint: lint/markdown lint/yaml test/styling test/static
 
 test/static:
-	cppcheck --enable=all \
-		--inconclusive \
-		--library=posix \
+	cppcheck \
+		--enable=all \
 		--std=c++17 \
+		--library=posix \
+		--inconclusive \
+		--inline-suppr \
+		--error-exitcode=13 \
 		--suppress=missingIncludeSystem \
+		--showtime=summary \
 		src/
 
 test/styling:
diff --git a/src/lib/exercises/include/exercises/hackerrank/warmup/simple_array_sum.hpp b/src/lib/exercises/include/exercises/hackerrank/warmup/simple_array_sum.hpp
index 6dd9072..b85346c 100644
--- a/src/lib/exercises/include/exercises/hackerrank/warmup/simple_array_sum.hpp
+++ b/src/lib/exercises/include/exercises/hackerrank/warmup/simple_array_sum.hpp
@@ -1,8 +1,7 @@
-#include <iostream>
 #include <vector>
 
 #pragma once
 
 namespace hackerrank::warmup {
-    int simpleArraySum(std::vector<int> ar);
+    int simpleArraySum(const std::vector<int>& ar);
 }
diff --git a/src/lib/exercises/src/hackerrank/warmup/simple_array_sum.cpp b/src/lib/exercises/src/hackerrank/warmup/simple_array_sum.cpp
index 19cb96a..aebefd8 100644
--- a/src/lib/exercises/src/hackerrank/warmup/simple_array_sum.cpp
+++ b/src/lib/exercises/src/hackerrank/warmup/simple_array_sum.cpp
@@ -4,26 +4,14 @@
  * @link Problem definition [[docs/hackerrank/warmup/simple_array_sum.md]]
  */
 
-#include <iostream>
-#include <cmath>
+#include <numeric>
 #include <vector>
 
-using namespace std;
-
-string ltrim(const string &);
-string rtrim(const string &);
-vector<string> split(const string &);
-
-
 namespace hackerrank::warmup {
 
-    int simpleArraySum(std::vector<int> ar) {
-        int accum = 0;
-
-        for(const int i : ar)  {
-            accum += i;
-        }
-        return accum;
+    int simpleArraySum(const std::vector<int>& ar) {
+        const int INIT_VALUE = 0;
+        return std::accumulate(ar.begin(), ar.end(), INIT_VALUE);
     }
 
 }
diff --git a/src/tests/unit/lib/foo.test.cpp b/src/tests/unit/lib/foo.test.cpp
index 9d2a727..82b305a 100644
--- a/src/tests/unit/lib/foo.test.cpp
+++ b/src/tests/unit/lib/foo.test.cpp
@@ -2,6 +2,7 @@
 
 #include <exercises/foo.hpp>
 
+// cppcheck-suppress unusedFunction
 TEST_CASE("adding numbers work", "[foo]")
 {
     CHECK(foo::add(0, 0) == 0);
diff --git a/src/tests/unit/lib/hackerrank/warmup/simple_array_sum.test.cpp b/src/tests/unit/lib/hackerrank/warmup/simple_array_sum.test.cpp
index c389d86..b63eeff 100644
--- a/src/tests/unit/lib/hackerrank/warmup/simple_array_sum.test.cpp
+++ b/src/tests/unit/lib/hackerrank/warmup/simple_array_sum.test.cpp
@@ -1,12 +1,11 @@
 #include <catch2/catch_test_macros.hpp>
 
 #include <exercises/hackerrank/warmup/simple_array_sum.hpp>
-#include <iostream>
 #include <vector>
-
 #include <filesystem>
 #include <fstream>
 #include <nlohmann/json.hpp>
+
 using json = nlohmann::json;
 
 TEST_CASE("simpleArraySum", "[warmup]")