From fe3bb68c183ab386b98758e6f388a45bf7defa2b Mon Sep 17 00:00:00 2001
From: stefiosif <stef8iosif@gmail.com>
Date: Wed, 20 Jul 2022 23:43:15 +0300
Subject: [PATCH] Add single vertex contains method and replace vertices field
 with adjMatrix' keys

---
 algorithm/breadth_first_search.h |  4 ++--
 algorithm/decremental_scc.h      |  4 ++--
 algorithm/tarjan.h               |  6 +++---
 graph/digraph.h                  |  2 --
 graph/graph.h                    | 24 ++++++++++++++----------
 5 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/algorithm/breadth_first_search.h b/algorithm/breadth_first_search.h
index 8bdb4b5..08b905b 100644
--- a/algorithm/breadth_first_search.h
+++ b/algorithm/breadth_first_search.h
@@ -27,8 +27,8 @@ private:
 template<typename T>
 std::map<T, bool> BreadthFirstSearch<T>::initExplore() {
   std::map<T, bool> graphExplore;
-  for (const auto& v : G.vertices) {
-    graphExplore[v] = false;
+  for (const auto& v : G.adjMatrix) {
+    graphExplore[v.first] = false;
   }
   return graphExplore;
 }
diff --git a/algorithm/decremental_scc.h b/algorithm/decremental_scc.h
index c8674ca..1ab6234 100644
--- a/algorithm/decremental_scc.h
+++ b/algorithm/decremental_scc.h
@@ -49,8 +49,8 @@ void DecrementalSCC<T>::findSCC() {
   for (auto& C : SCCs) {
     const auto& w = C.representative();
 
-    for (const auto& v : C.vertices)
-      A[v] = w;
+    for (const auto& v : C.adjMatrix)
+      A[v.first] = w;
     
     outTree[w] =
       BreadthFirstTree<T>(BreadthFirstSearch<T>(C).execute(w));
diff --git a/algorithm/tarjan.h b/algorithm/tarjan.h
index fd18387..1817bba 100644
--- a/algorithm/tarjan.h
+++ b/algorithm/tarjan.h
@@ -66,9 +66,9 @@ void Tarjan<T>::strongConnect(const T& v) {
 
 template<typename T>
 std::vector<SCC<T>> Tarjan<T>::execute() {
-  for (const auto& v : G.vertices) {
-    if (p[v].index == -1) {
-      strongConnect(v);
+  for (auto& v : G.adjMatrix) {
+    if (p[v.first].index == -1) {
+      strongConnect(v.first);
     }
   }
 
diff --git a/graph/digraph.h b/graph/digraph.h
index bdf5769..c10f1b6 100644
--- a/graph/digraph.h
+++ b/graph/digraph.h
@@ -22,8 +22,6 @@ public:
 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>
diff --git a/graph/graph.h b/graph/graph.h
index ed81c23..7e2bae6 100644
--- a/graph/graph.h
+++ b/graph/graph.h
@@ -18,6 +18,9 @@ public:
   // Return true if e(u,v) exists
   virtual bool contains(const T& u, const T& v);
 
+  // Return true if vertex u exists
+  virtual bool contains(const T& u);
+
   // Remove edge e(u,v)
   virtual void remove(const T& u, const T& v);
 
@@ -31,20 +34,16 @@ public:
   virtual void output();
 
   // Adjacency matrix representation
-  std::set<T> vertices;
   std::map<T, std::set<T>> adjMatrix;
 };
 
 template<typename T>
 Graph<T>::~Graph() {
-  vertices.clear();
   adjMatrix.clear();
 }
 
 template<typename T>
 inline void Graph<T>::insert(const T& u, const T& v) {
-  Graph<T>::vertices.insert(u);
-  Graph<T>::vertices.insert(v);
   Graph<T>::adjMatrix[u].insert(v);
 }
 
@@ -53,6 +52,11 @@ bool Graph<T>::contains(const T& u, const T& v) {
   return adjMatrix[u].contains(v);
 }
 
+template<typename T>
+bool Graph<T>::contains(const T& u) {
+  return adjMatrix.contains(u);
+}
+
 template<typename T>
 void Graph<T>::remove(const T& u, const T& v) {
   adjMatrix[u].erase(v);
@@ -60,23 +64,23 @@ void Graph<T>::remove(const T& u, const T& v) {
 
 template<typename T>
 std::uint16_t Graph<T>::V() {
-  return static_cast<std::uint16_t>(vertices.size());
+  return static_cast<std::uint16_t>(adjMatrix.size());
 }
 
 template<typename T>
 std::uint16_t Graph<T>::E() {
   std::uint16_t edges = 0;
-  for (const auto& v : vertices) {
-    edges += static_cast<std::uint16_t>(adjMatrix[v].size());
+  for (const auto& v : adjMatrix) {
+    edges += static_cast<std::uint16_t>(v.second.size());
   }
   return static_cast<std::uint16_t>(edges);
 }
 
 template<typename T>
 void Graph<T>::output() {
-  for (const auto& v : vertices) {
-    for (const auto& u : adjMatrix[v]) {
-      std::cout << v << "->" << u << '|';
+  for (const auto& v : adjMatrix) {
+    for (const auto& u : v.second) {
+      std::cout << v.first << "->" << u << '|';
     }
     std::cout << '\n';
   }