Replace map for edge indexing

bnb/graph.cpp

 #include <gp-bnb/graph.hpp>
 
-graph::graph(std::vector<std::vector<unsigned int>> a) : nodes_(a.size()), adjacency_list_(a) {
+graph::graph(std::vector<std::vector<unsigned int>> a) : nodes_(a.size()), adjacency_list_(a), indexed_edges_(a) {
 	// indexes the edges
-	edge_id eid = 0;
+	std::vector<std::pair<node_id,node_id>> edge_list;
 	
 	for (node_id u = 1; u <= nodes_; u++) {
-		const std::vector<node_id> & neighbors = get_adjacency(u);
-        
-		for (node_id v : neighbors) {			
+		for (node_id v : get_adjacency(u)) {			
             if (u < v) {
-                auto node_pair = std::make_pair(u, v);
-                indexed_edges_[node_pair] = eid;
-                eid++;
+                edge_list.push_back(std::make_pair(u,v));
             }
 		}
 	}
+	
+	edges_ = edge_list.size();
+
+	for (edge_id e = 1; e <= edges_; e++) {
+		node_id u = edge_list[e-1].first;
+		node_id v = edge_list[e-1].second;
+		const std::vector<node_id>& u_neighbors = get_adjacency(u);
+		const std::vector<node_id>& v_neighbors = get_adjacency(v);
+		for (unsigned int i = 0; i < u_neighbors.size(); i++) {
+			if (u_neighbors[i] == v) {
+				indexed_edges_[u-1][i] = e;
+				break;
+			}
+		}
+		for (unsigned int i = 0; i < v_neighbors.size(); i++) {
+			if (v_neighbors[i] == u) {
+				indexed_edges_[v-1][i] = e;
+				break;
+			}
+		}
+	}
 
 }
 
 edge_id graph::get_edge_id(node_id u, node_id v) const {
-    if (u < v) return indexed_edges_.at(std::make_pair(u, v));
-    else return indexed_edges_.at(std::make_pair(v, u));
-}
\ No newline at end of file
+	const std::vector<node_id>& neighbors = get_adjacency(u);
+	for (unsigned int i = 0; i < neighbors.size(); ++i) {
+		if (neighbors[i] == v) return indexed_edges_[u-1][i];
+	}
+	return 0;
+}

include/gp-bnb/graph.hpp

@@ -2,7 +2,6 @@
 #define GRAPH_HPP
 
 #include <vector>
-#include <map>
 
 using node_id = unsigned int; 
 using edge_id = unsigned int;
@@ -27,7 +26,7 @@ public:
      *  @return Number of edges after have been indexed
      */
     unsigned int num_edges() const {
-        return indexed_edges_.size();
+        return edges_;
     };
 
     /** @brief  Provides access to the adjacency of a node  
@@ -46,8 +45,9 @@ public:
 
 private:
     unsigned int nodes_;
+	unsigned int edges_;
 	std::vector<std::vector<unsigned int>> adjacency_list_;
-    std::map<std::pair<node_id,node_id>, edge_id> indexed_edges_;
+    std::vector<std::vector<edge_id>> indexed_edges_;
 };
 
 #endif