Add solution for 2016 Day 23

src/common/lib/Helper.h

@@ -11,6 +11,7 @@
 #include <map>
 #include <numeric>
 #include <set>
+#include <variant>
 #include <vector>
 
 #include "Array2D.h"
@@ -33,6 +34,9 @@ static std::ostream& operator<<(std::ostream& stream, const std::map<T, S>& cont
 template <typename T, typename S>
 static std::ostream& operator<<(std::ostream& stream, const std::pair<T, S>& pair);
 
+template <typename Arg1, typename Arg2, typename... Args>
+static std::ostream& operator<<(std::ostream& stream, const std::variant<Arg1, Arg2, Args...>& variant);
+
 struct Helper
 {
   struct ScopedTraceErrorDisabler
@@ -639,3 +643,10 @@ static std::ostream& operator<<(std::ostream& stream, const std::pair<T, S>& pai
 {
   return stream << "(" << pair.first << ", " << pair.second << ")";
 }
+
+template <typename Arg1, typename Arg2, typename... Args>
+static std::ostream& operator<<(std::ostream& stream, const std::variant<Arg1, Arg2, Args...>& variant)
+{
+  std::visit([&stream](const auto& value) { stream << value; }, variant);
+  return stream;
+}