From 2175ac0ca9f3d1c4ca6b13d7f34df5f528488735 Mon Sep 17 00:00:00 2001
From: stefiosif <stef8iosif@gmail.com>
Date: Fri, 10 Feb 2023 18:20:00 +0200
Subject: [PATCH] Add contains method for single vertex and hash function for
 SCCs

---
 include/graph/digraph.h | 26 ++++++++++++++++++++++++++
 include/graph/graph.h   | 20 +++-----------------
 include/graph/scc.h     | 26 ++++++++++++++++++--------
 3 files changed, 47 insertions(+), 25 deletions(-)

diff --git a/include/graph/digraph.h b/include/graph/digraph.h
index 371659a..9a88d98 100644
--- a/include/graph/digraph.h
+++ b/include/graph/digraph.h
@@ -24,6 +24,12 @@ public:
 
   // Reverse graph directions
   auto reverse();
+
+  //
+  auto contains(const T& u);
+
+  friend std::ostream& operator<<<>(std::ostream& os, Digraph<T>& G);
+
 };
 
 template<typename T>
@@ -60,6 +66,26 @@ auto Digraph<T>::reverse() {
   return revMatrix;
 }
 
+template<typename T>
+auto Digraph<T>::contains(const T& u) {
+  return this->adjList.count(u);
+}
+
+template<typename T>
+std::ostream& operator<<(std::ostream& os, Digraph<T>& G) {
+  os << "V: " << G.V() << " E: " << G.E() << '\n';
+  for (const auto& u : G.vertices()) {
+    if (!G.adjList[u].empty()) {
+      for (const auto& v : G.adjList[u]) {
+        os << u << "->" << v << ' ';
+      }
+      os << '\n';
+    }
+  }
+  os << '\n';
+  return os;
+}
+
 } // namespace graph
 
 #endif
\ No newline at end of file
diff --git a/include/graph/graph.h b/include/graph/graph.h
index c30462b..1058bfd 100644
--- a/include/graph/graph.h
+++ b/include/graph/graph.h
@@ -27,7 +27,7 @@ public:
   virtual void remove(const T& u, const T& v) =0;
 
   // Return graph vertices
-  auto vertices();
+  auto vertices() const;
 
   // Return num. of vertices
   std::uint16_t V();
@@ -38,11 +38,10 @@ public:
   // Adjacency matrix representation
   std::unordered_map<T, std::unordered_set<T>> adjList;
 
-  friend std::ostream& operator<<<>(std::ostream& os, Graph<T>& G);
 };
 
 template<typename T>
-auto Graph<T>::vertices() {
+auto Graph<T>::vertices() const{
   return std::views::keys(adjList);
 }
 
@@ -60,20 +59,7 @@ std::uint16_t Graph<T>::E() {
   return edges;
 }
 
-template<typename T>
-std::ostream& operator<<(std::ostream& os, Graph<T>& G) {
-  os << "V: " << G.V() << " E: " << G.E() << '\n';
-  for (const auto& u : this->vertices()) {
-    if (!this->adjList[u].empty()) {
-      for (const auto& v : this->adjList[u]) {
-        os << u << "->" << v << ' ';
-      }
-      os << '\n';
-    }
-  }
-  os << '\n';
-  return os;
-}
+
 
 } // namespace graph
 
diff --git a/include/graph/scc.h b/include/graph/scc.h
index 8d51af1..d1878a2 100644
--- a/include/graph/scc.h
+++ b/include/graph/scc.h
@@ -18,11 +18,14 @@ public:
 
   SCC(Digraph<T> G, T id) : id(id) { normalize(); }
 
-  // Return true if v is part of this SCC
-  bool member(const T& v);
+  // Return true if u is part of this SCC
+  bool contains(const T& u) const;
 
   // Representative vertex of this SCC
-  T id;
+  T id{};
+
+  // 
+  std::unordered_map<T, std::unordered_set<T>> neighboorList;
 
   bool operator==(const SCC& o) const;
 private:
@@ -34,25 +37,32 @@ template<typename T>
 void SCC<T>::normalize() {
   for (const auto& u : this->vertices()) {
     for (const auto& v : this->adjList[u]) {
-      if (!this->adjList.count(v)) {
+      if (!this->contains(v)) {
         this->adjList[u].erase(v);
         this->adjList.erase(v);
+        neighboorList[u].insert(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();
+bool SCC<T>::contains(const T& u) const {
+  return this->adjList.count(u);
 }
 
 template<typename T>
-bool SCC<T>::operator==(const SCC& o) const{
+bool SCC<T>::operator==(const SCC& o) const {
   return id == o.id;
 }
 
+template<typename T>
+struct HashSCC {
+  std::size_t operator()(const SCC<T>& C) const {
+    return static_cast<std::size_t>(C.id);
+  }
+};
+
 }; // namespace graph
 
 #endif
\ No newline at end of file