add transpose of a directed graph

Author: xtaci

include/directed_graph.h

@@ -26,15 +26,13 @@
 #include "graph_defs.h"
 #include "double_linked_list.h"
 
-namespace alg
-{
+namespace alg {
 class DirectedGraph:public Graph {
 private:
 /**
  * delete a vertex from adjacent lists
  */
-void delete_me(uint32_t id)
-{
+void delete_me(uint32_t id) {
 // delete every connection, iterator through every adjacent list
 Adjacent * adj;
 list_for_each_entry(adj, &a_head, a_node){
@@ -77,8 +75,7 @@ namespace alg
 /**
  * delete a vertex with specified id 
  */
-void delete_vertex(uint32_t id)
-{
+void delete_vertex(uint32_t id) {
 Adjacent * a = (*this)[id];
 if (a==NULL) return;
 delete_me(id);
@@ -92,8 +89,7 @@ namespace alg
 /**
  * create a new vertex and add to the graph, with specified id.
  */
-bool add_vertex(uint32_t id)
-{
+bool add_vertex(uint32_t id) {
 if ((*this)[id]!=NULL) return false;
 
 // new empty adjacent list
@@ -107,8 +103,7 @@ namespace alg
 /**
  * add an edge for x -> y
  */
-bool add_edge(uint32_t x, uint32_t y, int32_t weight)
-{
+bool add_edge(uint32_t x, uint32_t y, int32_t weight) {
 struct Adjacent * a1 = (*this)[x];
 struct Adjacent * a2 = (*this)[y];
 
@@ -130,8 +125,7 @@ namespace alg
 /**
  * delete an edge for x -> y
  */
-void delete_edge(uint32_t x, uint32_t y)
-{
+void delete_edge(uint32_t x, uint32_t y) {
 struct Adjacent * a1 = (*this)[x];
 struct Adjacent * a2 = (*this)[y];
 if (a1==NULL || a2==NULL) return ;
@@ -148,6 +142,24 @@ namespace alg
 }
 }
 }
+
+/**
+ * create the transpose of a directed-graph
+ */
+DirectedGraph * tranpose() {
+DirectedGraph * trans = new DirectedGraph;
+Adjacent * a;
+list_for_each_entry(a, &a_head, a_node){
+trans->add_vertex(a->v.id);
+Vertex * v;
+list_for_each_entry(v, &a->v_head, v_node){
+trans->add_vertex(v->id);
+trans->add_edge(v->id, a->v.id, v->weight);
+}
+}
+
+return trans;
+}
 };
 }