Add BFS tree

graph/graph.h

@@ -23,6 +23,13 @@ public:
   // Reverse graph directions
   Graph<T> reverse();
 
+  // Number of vertices
+  std::uint16_t V();
+
+  // Number of edges
+  // TODO: Calculate bidirectional edges once
+  std::uint16_t E();
+
   // Adjacency matrix representation
   std::set<T> vertices;
   std::map<T, std::set<T>> adjMatrix;
@@ -45,6 +52,20 @@ Graph<T> Graph<T>::reverse() {
   return Graph<T>();
 }
 
+template<typename T>
+std::uint16_t Graph<T>::V() {
+  return vertices.size();
+}
+
+template<typename T>
+std::uint16_t Graph<T>::E() {
+  std::uint16_t edges = 0;
+  for (const auto& v : vertices) {
+    edges += adjMatrix[v].size();
+  }
+  return edges;
+}
+
 } // namespace graph
 
 #endif