diff --git a/include/boost/graph/adj_list_serialize.hpp b/include/boost/graph/adj_list_serialize.hpp
index 85f7e2ed4..381f0a455 100644
--- a/include/boost/graph/adj_list_serialize.hpp
+++ b/include/boost/graph/adj_list_serialize.hpp
@@ -9,6 +9,8 @@
 #ifndef BOOST_GRAPH_ADJ_LIST_SERIALIZE_HPP
 #define BOOST_GRAPH_ADJ_LIST_SERIALIZE_HPP
 
+#include <unordered_map>
+
 #include <boost/graph/adjacency_list.hpp>
 #include <boost/graph/iteration_macros.hpp>
 #include <boost/pending/property_serialize.hpp>
@@ -43,17 +45,17 @@ namespace serialization
         const unsigned int /* file_version */
     )
     {
-        typedef adjacency_list< OEL, VL, D, VP, EP, GP, EL > Graph;
-        typedef typename graph_traits< Graph >::vertex_descriptor Vertex;
+        using Graph = adjacency_list< OEL, VL, D, VP, EP, GP, EL >;
+        using Vertex = typename graph_traits< Graph >::vertex_descriptor;
 
-        int V = num_vertices(graph);
-        int E = num_edges(graph);
+        const auto V = num_vertices(graph);
+        const auto E = num_edges(graph);
         ar << BOOST_SERIALIZATION_NVP(V);
         ar << BOOST_SERIALIZATION_NVP(E);
 
         // assign indices to vertices
-        std::map< Vertex, int > indices;
-        int num = 0;
+        std::unordered_map< Vertex, Vertex > indices(V);
+        Vertex num = 0;
         BGL_FORALL_VERTICES_T(v, graph, Graph)
         {
             indices[v] = num++;
@@ -81,33 +83,37 @@ namespace serialization
         const unsigned int /* file_version */
     )
     {
-        typedef adjacency_list< OEL, VL, D, VP, EP, GP, EL > Graph;
-        typedef typename graph_traits< Graph >::vertex_descriptor Vertex;
-        typedef typename graph_traits< Graph >::edge_descriptor Edge;
+        using Graph = adjacency_list< OEL, VL, D, VP, EP, GP, EL >;
+        using Vertex = typename graph_traits< Graph >::vertex_descriptor;
+        using Edge = typename graph_traits< Graph >::edge_descriptor;
+        using VertexSizeType = typename graph_traits< Graph >::vertices_size_type;
 
-        unsigned int V;
+        VertexSizeType V;
         ar >> BOOST_SERIALIZATION_NVP(V);
-        unsigned int E;
+        
+        VertexSizeType E;
         ar >> BOOST_SERIALIZATION_NVP(E);
 
         std::vector< Vertex > verts(V);
-        int i = 0;
+        size_t i = 0;
         while (V-- > 0)
         {
-            Vertex v = add_vertex(graph);
+            const auto v = add_vertex(graph);
             verts[i++] = v;
             ar >> serialization::make_nvp(
                 "vertex_property", get(vertex_all_t(), graph, v));
         }
+        
         while (E-- > 0)
         {
-            int u;
-            int v;
+            Vertex u;
+            Vertex v;
             ar >> BOOST_SERIALIZATION_NVP(u);
             ar >> BOOST_SERIALIZATION_NVP(v);
+
             Edge e;
             bool inserted;
-            boost::tie(e, inserted) = add_edge(verts[u], verts[v], graph);
+            boost::tie(e, inserted)= add_edge(verts[u], verts[v], graph);
             ar >> serialization::make_nvp(
                 "edge_property", get(edge_all_t(), graph, e));
         }