diff --git a/graph/digraph.h b/graph/digraph.h
index 92ecaf2..bdf5769 100644
--- a/graph/digraph.h
+++ b/graph/digraph.h
@@ -16,7 +16,7 @@ public:
   Digraph(std::map<T, std::set<T>> digraph);
 
   // Reverse graph directions
-  Digraph<T> reverse();
+  auto reverse();
 };
 
 template<typename T>
@@ -27,7 +27,7 @@ Digraph<T>::Digraph(std::map<T, std::set<T>> digraph) {
 }
 
 template<typename T>
-Digraph<T> Digraph<T>::reverse() {
+auto Digraph<T>::reverse() {
   std::map<T, std::set<T>> revMatrix;
   
   for (const auto& v : Graph<T>::adjMatrix) {