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>();

graph/scc.h

@@ -12,8 +12,13 @@ class SCC : public Graph<T> {
 public:
   SCC(std::map<T, std::set<T>> scc);
 
+  //
+  T representative() { return proxy; };
 private:
-  T root;
+  // Each SCC has a representative vertex that helps
+  // answer strong connectivity queries in O(1) time
+  T proxy;
+
 };
 
 template<typename T>
@@ -21,7 +26,7 @@ SCC<T>::SCC(std::map<T, std::set<T>> scc) {
   Graph<T>::adjMatrix = scc;
   auto kv = std::views::keys(Graph<T>::adjMatrix);
   Graph<T>::vertices = std::set<T>{ kv.begin(), kv.end() };
-  root = scc.begin()->first;
+  proxy = scc.begin()->first;
 }
 
 }; // namespace graph