Add roditty and zwick class

graph/digraph.h

@@ -4,6 +4,7 @@
 #include "graph.h"
 
 #include <algorithm>
+#include <ranges>
 
 namespace graph {
 
@@ -12,10 +13,19 @@ class Digraph : public Graph<T> {
 public:
   Digraph() = default;
 
+  Digraph(std::map<T, std::set<T>> digraph);
+
   // Reverse graph directions
   Digraph<T> reverse();
 };
 
+template<typename T>
+Digraph<T>::Digraph(std::map<T, std::set<T>> digraph) {
+  Graph<T>::adjMatrix = digraph;
+  auto kv = std::views::keys(Graph<T>::adjMatrix);
+  Graph<T>::vertices = std::set<T>{ kv.begin(), kv.end() };
+}
+
 template<typename T>
 Digraph<T> Digraph<T>::reverse() {
   return Digraph<T>();