change cout to clog

day9/day.cpp

@@ -15,7 +15,7 @@ void printDiskMap(std::vector<int> &diskmap) {
       std::clog << numC << diskmap[i] << RESET;
     }
   }
-  std::cout << RESET << std::endl;
+  std::clog << RESET << std::endl;
 }
 int main() {
   std::ifstream inputfile("input");