2 files changed, 61 insertions, 12 deletions

diff --git a/src/graph.c b/src/graph.c
index 4be2b44..cf45e2b 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -1,16 +1,56 @@
 #include "graph.h"
+#include "linked_list.h"
 #include <stdlib.h>
 
+// Need to declare 'graph_delete' for use in 'graph_new'
+void graph_delete(Graph *g);
+
 Graph *graph_new(int n) {
-    Graph *graph = malloc(sizeof(Graph));
-    if (!graph) return NULL;
+    Graph *graph = (Graph *)malloc(sizeof(Graph));
+    if (!graph)
+        return NULL;
+
+    graph->vertices = (Vertex *)malloc(sizeof(Vertex) * n);
+    if (!graph->vertices) {
+        free(graph);
+        return NULL;
+    }
 
     graph->numEdges = n;
     graph->numVertices = 0;
-    graph->vertices = malloc(sizeof(Vertex[n]));
+    
+    for (int i = 0; i < n; i++) {
+        graph->vertices[i].id = i;
+        graph->vertices[i].outNeighbours = linked_list_new();
+        graph->vertices[i].inNeighbours = linked_list_new();
+
+        // if allocation for the linked lists failed
+        if (!graph->vertices[i].outNeighbours
+            || !graph->vertices[i].inNeighbours) {
+            graph_delete(graph);
+            return NULL;
+        }
+    }
 
     return graph;
 }
 
 void graph_add_edge(Graph *g, int i, int j) {
+    linked_list_append(g->vertices[i].outNeighbours, &g->vertices[j]);
+    linked_list_append(g->vertices[j].inNeighbours, &g->vertices[i]);
+    g->numEdges++;
+}
+
+Graph *graph_read(const char *filename) {
+    Graph *g = graph_new(69);
+    return g;
+}
+
+void graph_delete(Graph *g) {
+    for (int i = 0; i < g->numVertices; i++) {
+        linked_list_delete(g->vertices[i].inNeighbours);
+        linked_list_delete(g->vertices[i].outNeighbours);
+    }
+    free(g->vertices);
+    free(g);
 }
diff --git a/src/linked_list.c b/src/linked_list.c
index 0a6850d..2e290e9 100644
--- a/src/linked_list.c
+++ b/src/linked_list.c
@@ -3,7 +3,8 @@
 
 LinkedList *linked_list_new(void) {
     LinkedList *ll = (LinkedList *)malloc(sizeof(LinkedList));
-    if (!ll) return NULL;
+    if (!ll)
+        return NULL;
 
     ll->head = NULL;
     ll->tail = NULL;
@@ -27,7 +28,8 @@ void linked_list_delete(LinkedList *ll) {
 
 LinkedListNode *linked_list_append(LinkedList *ll, void *elem) {
     LinkedListNode *new_node = (LinkedListNode *)malloc(sizeof(LinkedListNode));
-    if (!new_node) return NULL;
+    if (!new_node)
+        return NULL;
 
     new_node->data = elem;
     new_node->next = NULL;
@@ -46,7 +48,8 @@ LinkedListNode *linked_list_append(LinkedList *ll, void *elem) {
 }
 
 void *linked_list_popfront(LinkedList *ll) {
-    if (!ll->head) return NULL;
+    if (!ll->head)
+        return NULL;
 
     void *elem = ll->head->data;
     LinkedListNode *node = ll->head;
@@ -58,13 +61,15 @@ void *linked_list_popfront(LinkedList *ll) {
 }
 
 LinkedListNode *linked_list_find(LinkedList *ll, void *elem) {
-    if (!ll->head) return NULL;
+    if (!ll->head)
+        return NULL;
 
     LinkedListNode *node = ll->head;
     while (node) {
         /* !NOTE should use a given comparator function
          * instead of '==' operator */
-        if (node->data == elem) return node;
+        if (node->data == elem)
+            return node;
         node = node->next;
     }
 
@@ -74,11 +79,15 @@ LinkedListNode *linked_list_find(LinkedList *ll, void *elem) {
 void *linked_list_remove(LinkedList *ll, LinkedListNode *node) {
     void *elem = node->data;
 
-    if (node->prev) node->prev->next = node->next;
-    else ll->head = node->next;
+    if (node->prev)
+        node->prev->next = node->next;
+    else
+        ll->head = node->next;
 
-    if (node->next) node->next->prev = node->prev;
-    else ll->tail = node->prev;
+    if (node->next)
+        node->next->prev = node->prev;
+    else
+        ll->tail = node->prev;
 
     free(node);
     ll->size--;