Fix clear_vertex() and remove_edge(s, t, g) in adj_list<>

src/graph/graph_adjacency.hh

@@ -548,6 +548,8 @@ inline Vertex add_vertex(adj_list<Vertex>& g)
 template <class Vertex>
 inline void clear_vertex(Vertex v, adj_list<Vertex>& g)
 {
+    if (!g._keep_epos)
+    {
         typename adj_list<Vertex>::edge_list_t& oes = g._out_edges[v];
         for (size_t i = 0; i < oes.size(); ++i)
         {
@@ -581,6 +583,41 @@ inline void clear_vertex(Vertex v, adj_list<Vertex>& g)
         }
         g._n_edges -= ies.size();
         ies.clear();
+    }
+    else
+    {
+        typename adj_list<Vertex>::edge_list_t& oes = g._out_edges[v];
+        for (size_t i = 0; i < oes.size(); ++i)
+        {
+            Vertex t = oes[i].first;
+            size_t idx = oes[i].second;
+            typename adj_list<Vertex>::edge_list_t& ies = g._in_edges[t];
+            const std::pair<int32_t, int32_t>& pos = g._epos[idx];
+
+            g._epos[ies.back().second].second = pos.second;
+            ies[pos.second] = ies.back();
+            ies.pop_back();
+            g._free_indexes.push_back(idx);
+        }
+        g._n_edges -= oes.size();
+        oes.clear();
+
+        typename adj_list<Vertex>::edge_list_t& ies = g._in_edges[v];
+        for (size_t i = 0; i < ies.size(); ++i)
+        {
+            Vertex s = ies[i].first;
+            size_t idx = ies[i].second;
+            typename adj_list<Vertex>::edge_list_t& oes = g._out_edges[s];
+            const std::pair<int32_t, int32_t>& pos = g._epos[idx];
+
+            g._epos[oes.back().second].first = pos.first;
+            oes[pos.first] = oes.back();
+            oes.pop_back();
+            g._free_indexes.push_back(idx);
+        }
+        g._n_edges -= ies.size();
+        ies.clear();
+    }
 }
 
 // O(V + E)
@@ -689,6 +726,8 @@ template <class Vertex>
 inline void remove_edge(Vertex s, Vertex t,
                         adj_list<Vertex>& g)
 {
+    if (!g._keep_epos)
+    {
         typename adj_list<Vertex>::edge_list_t& oes = g._out_edges[s];
         for (size_t i = 0; i < oes.size(); ++i)
         {
@@ -706,6 +745,11 @@ inline void remove_edge(Vertex s, Vertex t,
             if (s == ies[i].first)
                 ies.erase(ies.begin() + i);
         }
+    }
+    else
+    {
+        remove_edge(edge(s, t, g).first, g);
+    }
 }
 
 template <class Vertex>