diff --git a/graph/scc.h b/graph/scc.h
index 94592e2..3ede212 100644
--- a/graph/scc.h
+++ b/graph/scc.h
@@ -3,6 +3,9 @@
 
 #include "digraph.h"
 
+#include <algorithm>
+#include <functional>
+
 namespace graph {
 
 template<typename T>
@@ -14,27 +17,36 @@ public:
 
   SCC(Digraph<T> G, T id) : id(id) { normalize(); }
 
+  // Return true if v is part of this SCC
+  bool member(const T& v);
+
+  // Representative vertex of this SCC
   T id;
 
   bool operator==(const SCC& o) const;
 private:
-  // For every vertex in the SCC, if there is an edge between an in-scc vertex
-  // and an out-scc vertex erase the edge between them and the out-scc vertex
+  // Erase all edges that include vertices outside this SCC
   void normalize();
 };
 
 template<typename T>
 void SCC<T>::normalize() {
-  for (const auto& u : this->adjMatrix) {
-    for (const auto& v : u.second) {
+  for (const auto& u : this->vertices()) {
+    for (const auto& v : this->adjMatrix[u]) {
       if (!this->adjMatrix.count(v)) {
-        this->adjMatrix[u.first].erase(v);
+        this->adjMatrix[u].erase(v);
         this->adjMatrix.erase(v);
       }
     }
   }
 }
 
+template<typename T>
+bool SCC<T>::member(const T& v) {
+  const auto& V = this->vertices();
+  return std::find(V.begin(), V.end(), v) != V.end();
+}
+
 template<typename T>
 bool SCC<T>::operator==(const SCC& o) const{
   return id == o.id;