Move headers into include folder and add single header to include all reachability algorithms

include/graph/graph.h

@@ -0,0 +1,86 @@
+#ifndef GRAPH_H_
+#define GRAPH_H_
+
+#include <unordered_map>
+#include <unordered_set>
+#include <ostream>
+#include <ranges>
+
+namespace graph {
+
+// Forward declerations
+template<typename T> class Graph;
+template<typename T> std::ostream& operator<<(std::ostream& os, Graph<T>& G);
+
+template<typename T>
+class Graph {
+public:
+  ~Graph();
+  
+  // Return true if there is a path from u to v
+  virtual bool contains(const T& u, const T& v) =0;
+
+  // Add edge e(u,v)
+  virtual void insert(const T& u, const T& v) =0;
+
+  // Remove edge e(u,v)
+  virtual void remove(const T& u, const T& v) =0;
+
+  // Return graph vertices
+  auto vertices();
+
+  // Return num. of vertices
+  std::uint16_t V();
+
+  // Return num. of edges
+  std::uint16_t E();
+
+  // 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>
+Graph<T>::~Graph() {
+  adjList.clear();
+}
+
+template<typename T>
+auto Graph<T>::vertices() {
+  return std::views::keys(adjList);
+}
+
+template<typename T>
+std::uint16_t Graph<T>::V() {
+  return static_cast<std::uint16_t>(adjList.size());
+}
+
+template<typename T>
+std::uint16_t Graph<T>::E() {
+  std::uint16_t edges = 0;
+  for (const auto& u : vertices()) {
+    edges += static_cast<std::uint16_t>(adjList[u].size());
+  }
+  return static_cast<std::uint16_t>(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
+
+
+#endif