Add OpenMP support. Doesnt really matter but why not

2025/Cpp/Day02/Day02.cpp

@@ -6,6 +6,14 @@
 #include <cstring>
 #include <sstream>
 
+#ifdef _MSVC
+#define _OPENMP 1
+#endif
+
+#ifdef _OPENMP
+#include <omp.h>
+#endif
+
 class Range {
 public:
     using range_t = long long;
@@ -123,6 +131,9 @@ public:
             auto left = range.left();
             auto right = range.right();
 
+        #ifdef _OPENMP
+            #pragma omp parallel for reduction(+ : sum)
+        #endif
             for (Range::range_t i = left; i <= right; i++) {
                 if (!isValidPart02(std::to_string(i)))
                     sum += i;