feat: finalize solution implementation for LC problem #3409

Author: rom.spiridonov

solution/3400-3499/3409.Longest Subsequence With Decreasing Adjacent Difference/Solution.cpp

@@ -1,6 +1,6 @@
-#include <vector>
 #include <algorithm>
 #include <ranges>
+#include <vector>
 using namespace std;
 using namespace std::ranges;