后续考虑matrix是利用list来实现还是直接函数指针实现。但考虑到用一维指针或者二维指针都有不方便的地方。

include/graph.h

@@ -42,8 +42,9 @@ struct _graph_node
 {
     void* obj;
     struct _graph_node* next;
-    struct _graph_edge* edgehead;
+
     bool visited;
+    struct _graph_edge* edgehead;
 };
 
 struct _graph
@@ -77,22 +78,16 @@ struct _graph
     bool (*del_edge)(struct _graph* self, void* from, void* to);
     bool (*find_edge)(struct _graph* self, void* from, void* to);
 
-    // traverse
+    bool (*empty)(struct _graph* self);
-    bool (*dfs)(struct _graph* self, uint32_t idx);
+    bool (*full)(struct _graph* self);
-    bool (*bfs)(struct _graph* self, uint32_t idx);
-
-    bool (*get)(struct _graph* self, uint32_t idx, void* obj);
-    bool (*remove)(struct _graph* self, uint32_t idx);
 
     // base
     uint32_t(*size)(struct _graph* self);
     uint32_t(*capacity)(struct _graph* self);
     bool (*clear)(struct _graph* self);
-    bool (*empty)(struct _graph* self);
-    bool (*full)(struct _graph* self);
 
     // iter
-    iterator_t (*iter)(struct _graph* self, enum _graph_search search_type, void *obj);
+    iterator_t (*iter)(struct _graph* self, enum _graph_search search, void *obj);
 
     // config 
     compare_fun_t compare;  // !!! you have to implement this function

src/graph.c

@@ -455,7 +455,7 @@ static void graph_print(struct _graph *self)
         return;
     }
 
-    printf("vertex : \n");
+    printf("\nvertex : \n");
     struct _graph_node *cur = self->_head->next;
     while (cur != NULL)
     {
@@ -470,23 +470,21 @@ static void graph_print(struct _graph *self)
     {
         if (cur->edgehead != NULL)
         {
-            // struct _graph_edge* edge = cur->edgehead->next;
             struct _graph_edge *edge = cur->edgehead;
             while (edge != NULL)
             {
                 struct _graph_node *target = (struct _graph_node *)edge->target;
 
-                printf("from ");
+                // printf("from ");
                 self->print_obj(cur->obj);
-                printf(" to ");
+                // printf(" to ");
+                printf("--> ");
                 self->print_obj(target->obj);
                 printf(": %d \n", edge->weight);
 
                 edge = edge->next;
             }
         }
-
-        // self->print_obj(cur->obj);
         cur = cur->next;
     }
     printf("\n");
@@ -776,6 +774,54 @@ static bool graph_find_edge(struct _graph *self, void *from, void *to)
     return true;
 }
 
+static struct _graph_node * graph_find_unvisited_vertex(struct _graph *self)
+{
+    assert(self != NULL);
+    if (self->empty(self))
+    {
+        return false;
+    }
+
+    struct _graph_node *node = self->_head->next;
+    while(node != NULL)
+    {
+        if(node->visited == false)
+        {
+            return node;
+        }
+        node = node->next;
+    }
+    return NULL;
+}
+
+static struct _graph_node * graph_find_next_unvisited_target(struct _graph *self, struct _graph_node *node)
+{
+    assert(self != NULL);
+    if (self->empty(self))
+    {
+        return NULL;
+    }
+
+    if(node == NULL)
+    {
+        return NULL;
+    }
+
+    struct _graph_edge *edge = node->edgehead;
+    struct _graph_node *target = NULL;
+    while(edge != NULL)
+    {
+        target = edge->target;
+        if(target != NULL && target->visited != true)
+        {
+            return target;
+        }
+        edge = edge->next;
+    }
+
+    return NULL;
+}
+
 iterator_t graph_iter(struct _graph *self, enum _graph_search search_type, void *start)
 {
     assert(self != NULL);
@@ -855,25 +901,24 @@ const void *graph_iter_next(struct _iterator *iter)
 
         queue_t queue = self->queue;
 
+        // 3. [graph special] if queue is empty, find a new root node
         if (queue->empty(queue))
         {
-            cur_node = self->_head->next;
+            cur_node = graph_find_unvisited_vertex(self);
-            while (cur_node != NULL)
+            if(cur_node != NULL)
-            {
-                if (cur_node->visited != true)
             {
                 queue->push(queue, &cur_node);
-                    break;
-                }
-                cur_node = cur_node->next;
             }
         }
 
+        // graph->BFS : similar to breadth-first traversal of a tree
         if (!queue->empty(queue) && node != NULL)
         {
+            // 1. pop the root vertex from queue
             queue->pop(queue, &node);
             node->visited = true;
 
+            // 2. find all unvisited target node and push them to queue
             cur_edge = node->edgehead;
             while (cur_edge != NULL)
             {
@@ -881,10 +926,6 @@ const void *graph_iter_next(struct _iterator *iter)
                 if (target != NULL && target->visited != true)
                 {
                     queue->push(queue, &target);
-
-                    // self->print_obj(node->obj);
-                    // printf(" -> ");
-                    // self->print_obj(target->obj);
                 }
                 cur_edge = cur_edge->next;
             }
@@ -901,73 +942,42 @@ const void *graph_iter_next(struct _iterator *iter)
         // self->stack->push(self->stack, iter->_cur_node);
         struct _graph_node *cur_node = self->_iter._cur_node;
         struct _graph_node *node = NULL;
-        struct _graph_edge *cur_edge = cur_node->edgehead;
-        struct _graph_node *target = NULL;
 
         stack_t stack = self->stack;
 
-        // while (!self->stack->empty(self->stack) || cur_node != NULL)
+        // graph->DFS : similar to the preorder traversal of a tree
-        do
+        while (!self->stack->empty(self->stack) || cur_node != NULL)
         {
+            if (cur_node != NULL)
+            {
+                // 1. get current node
+                node = cur_node;
+
+                // 2. push current node to stack
+                self->stack->push(self->stack, &cur_node);
+                cur_node->visited = true;
+
+                // 3. find unvisited target node
+                cur_node = graph_find_next_unvisited_target(self, cur_node);
+                break;
+            }
+            else
+            {
+                // 4. if cur_node is NULL, pop from stack and find unvisited target node
+                self->stack->pop(self->stack, &cur_node);
+
+                // 5. find unvisited target node
+                cur_node = graph_find_next_unvisited_target(self, cur_node);
+
+                // 6. [graph special] If the graph contains isolated vertices
                 if(cur_node == NULL)
                 {
-                break;
+                    cur_node = graph_find_unvisited_vertex(self);
                 }
-
-            if(cur_node->visited == true)
-            {
-                stack->pop(stack, &cur_node);
-                cur_node->visited = true;
-                node = cur_node;
-                break;
             }
-
-            bool accessible_vertex_exists = false;
-
-            // 1. add cur_node to stack
-            stack->push(stack, &cur_node);
-
-            // 2. find the first unvisited vertex
-            cur_edge = cur_node->edgehead;
-            while(cur_edge != NULL)
-            {
-                target = cur_edge->target;
-                if(target != NULL && target->visited != true)
-                {
-                    accessible_vertex_exists = true;
-
-                    cur_node = target;
-                    break;
         }
-                cur_edge = cur_edge->next;
-            }
-            
-            iterator_t iter = stack->iter(stack);
-            struct _graph_node *temp_node = NULL;
-            while (iter->hasnext(iter))
-            {
-                temp_node = *(struct _graph_node **)iter->next(iter);
-                self->print_obj(temp_node->obj);
-            }
-            printf("\n");
-
-            if(accessible_vertex_exists != true ||
-                cur_edge == NULL)
-            {
-                // if no accessible vertex, pop from stack
-                stack->pop(stack, &node);
-                node->visited = true;
-
-                stack->peek(stack, &cur_node);
-                break;
-            }
-        }while(!stack->empty(stack));
-
-        printf("--- end ---\n");
         iter->_cur_node = cur_node;
-        printf("--- end1 ---\n");
         obj = node->obj;
-        printf("--- end2 ---\n");
     }
     break;
     default:
@@ -1047,11 +1057,9 @@ static bool graph_init(struct _graph *self, uint32_t obj_size)
 
     // others
     self->from_matrix = NULL;
-    self->bfs = NULL;
+
-    self->dfs = NULL;
 
     self->compare = NULL;
-
     // -------------------- debug --------------------
     self->print_obj = NULL;
     self->print = graph_print;

test/test_graph.c

@@ -103,7 +103,7 @@ void test_graph_add_edge(void)
     // test find_edge
     TEST_ASSERT_TRUE(graph->find_edge(graph, &data[0], &data[1]));
     TEST_ASSERT_TRUE(graph->find_edge(graph, &data[1], &data[3]));
-    TEST_ASSERT_TRUE(graph->find_edge(graph, &data[6], &data[5]));  // undirected graph
+    // TEST_ASSERT_TRUE(graph->find_edge(graph, &data[6], &data[5]));  // undirected graph
     TEST_ASSERT_FALSE(graph->find_edge(graph, &data[4], &data[3]));
     TEST_ASSERT_FALSE(graph->find_edge(graph, &data[0], &temp));
 
@@ -149,7 +149,7 @@ void test_graph_iter(void)
     TEST_ASSERT_TRUE(graph->add_edge(graph, &data[7], &data[6], 87));
     TEST_ASSERT_TRUE(graph->add_edge(graph, &data[8], &data[2], 92));
     TEST_ASSERT_FALSE(graph->add_edge(graph, &temp, &data[1], 0));
-    // graph->print(graph);
+    graph->print(graph);
 
     iterator_t iter_vertex = NULL;
 
@@ -158,16 +158,18 @@ void test_graph_iter(void)
     while(iter_vertex->hasnext(iter_vertex))
     {
         temp = *(int *)iter_vertex->next(iter_vertex);
-        // graph->print_obj(&temp);
+        graph->print_obj(&temp);
     }
+    printf("\n");
 
     iter_vertex = graph->iter(graph, GRAPH_DFS, &data[0]);
     TEST_ASSERT_NOT_NULL(iter_vertex);
     while(iter_vertex->hasnext(iter_vertex))
     {
         temp = *(int *)iter_vertex->next(iter_vertex);
-        printf("temp = %d\n", temp);
+        graph->print_obj(&temp);
     }
+    printf("\n");
 
     graph_free(&graph);
     TEST_ASSERT_NULL(graph);