Add method to access adjMatrix keys and add adjMatrix on seaching method

graph/digraph.h

@@ -4,6 +4,8 @@
 #include "graph.h"
 #include "algorithm/breadth_first_search.h"
 
+#include <ranges>
+
 namespace graph {
 
 template<typename T>
@@ -24,6 +26,9 @@ public:
 
   // Reverse graph directions
   auto reverse();
+
+  // Return vertices
+  auto vertices();
 };
 
 template<typename T>
@@ -33,7 +38,7 @@ Digraph<T>::Digraph(std::map<T, std::set<T>> G) {
 
 template<typename T>
 bool Digraph<T>::contains(const T& u, const T& v) {
-  return algo::BreadthFirstSearch<T>().query(u, v);
+  return algo::BreadthFirstSearch<T>(this->adjMatrix).query(u, v);
 }
 
 template<typename T>
@@ -62,6 +67,11 @@ auto Digraph<T>::reverse() {
   return revMatrix;
 }
 
+template<typename T>
+auto Digraph<T>::vertices() {
+  return std::views::keys(this->adjMatrix);
+}
+
 } // namespace graph
 
 #endif