Small changes

4 files changed, 43 insertions, 29 deletions

diff --git a/README.md b/README.md
index ea29f50..4581aa9 100644
--- a/README.md
+++ b/README.md
@@ -74,3 +74,14 @@ To list all available build targets and their descriptions:
 ```bash
 make help
 ```
+
+## Adjacency List Storage: Linked List vs Array
+
+Two approaches for storing graph neighbors: linked lists and dynamic arrays.
+Benchmarks show no measurable performance difference
+despite vectors offering better cache locality.
+
+Why? Kahn's algorithm is $O(V+E) $, so memory access patterns
+likely isn't the bottleneck.
+
+Cache locality could become a bottleneck on huge graphs
diff --git a/src/cycle_detection.c b/src/cycle_detection.c
index d232d89..8dd5691 100644
--- a/src/cycle_detection.c
+++ b/src/cycle_detection.c
@@ -9,12 +9,19 @@
 void cycle_detection(Graph *g) {
     int n = g->num_vertices;
     int *indegree = calloc(n, sizeof(int));
+    if (!indegree) {
+        fprintf(stderr, "Memory allocation failed: could not create list.\n");
+        free(indegree);
+        return;
+    }
+
     LinkedList *queue = linked_list_new();
     if (!queue) {
         fprintf(stderr, "Memory allocation failed: could not create queue.\n");
         free(indegree);
         return;
     }
+
     Vector *list = vector_new();
     if (!list) {
         fprintf(stderr, "Memory allocation failed: could not create vector.\n");
@@ -22,7 +29,7 @@ void cycle_detection(Graph *g) {
         linked_list_delete(queue);
         return;
     }
-    
+
     // Compute in-degrees
     for (int i = 0; i < n; i++) {
         for (int j = 0; j < (int)g->vertices[i].out_neighbours->size; j++) {
@@ -30,19 +37,19 @@ void cycle_detection(Graph *g) {
             indegree[neighbor]++;
         }
     }
-    
+
     // Add all vertices with no incoming edges
     for (int i = 0; i < n; i++) {
-        if (!indegree[i]) {
+        if (indegree[i] == 0) {
             linked_list_append(queue, (void *)(intptr_t)i);
         }
     }
-    
+
     // Process queue for topological sort
-    while (queue->size) {
+    while (queue->size != 0) {
         int top = (int)(intptr_t)linked_list_popfront(queue);
         vector_push(list, (void *)(intptr_t)top);
-        
+
         // Process all neighbors of current vertex
         for (int j = 0; j < (int)g->vertices[top].out_neighbours->size; j++) {
             int neighbor = *(int *)g->vertices[top].out_neighbours->data[j];
@@ -52,11 +59,11 @@ void cycle_detection(Graph *g) {
             }
         }
     }
-    
+
     // Output result
-    if ((int)list->size != n) {
+    if ((int)list->size != n)
         fprintf(stdout, "CYCLE DETECTED!\n");
-    } else {
+    else {
         for (int i = 0; i < (int)list->size; i++) {
             if (i != 0)
                 fprintf(stdout, ", ");
@@ -64,7 +71,7 @@ void cycle_detection(Graph *g) {
         }
         fprintf(stdout, "\n");
     }
-    
+
     linked_list_delete(queue);
     vector_delete(list);
     free(indegree);
diff --git a/src/graph.c b/src/graph.c
index 44ce400..8c19a19 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -20,7 +20,7 @@ Graph *graph_new(int n) {
 
     graph->num_edges = 0;
     graph->num_vertices = n;
-    
+
     for (int i = 0; i < n; i++) {
         graph->vertices[i].id = i;
         graph->vertices[i].out_neighbours = vector_new();
@@ -47,46 +47,42 @@ Graph *graph_read(const char *filename) {
     FILE *file = fopen(filename, "r");
     if (!file)
         return NULL;
-    
-    char line[1024];
+
+    char line[4096];
+
     if (!fgets(line, sizeof(line), file)) {
         fclose(file);
         return NULL;
     }
-    
+
     int n = atoi(line);
     if (n <= 0) {
         fclose(file);
         return NULL;
     }
-    
+
     Graph *g = graph_new(n);
     if (!g) {
         fclose(file);
         return NULL;
     }
-    
-    for (int i = 0; i < n; i++) {
+
+    for (int row = 0; row < n; row++) {
         if (!fgets(line, sizeof(line), file)) {
-            fprintf(stderr, "Error: Could not read row %d\n", i);
             fclose(file);
             return g;
         }
-        
-        int j = 0;
+
         int col = 0;
-        while (col < n && line[j] != '\0' && line[j] != '\n') {
-            if (line[j] == '1') {
-                graph_add_edge(g, i, col);
-                col++;
-            } else if (line[j] == '0') {
+        for (int i = 0; line[i] != EOF && line[i] != '\n'; i++) {
+            if (line[i] == '0' || line[i] == '1') {
+                if (line[i] == '1')
+                    graph_add_edge(g, row, col);
                 col++;
             }
-            // skip any other characters
-            j++;
         }
     }
-    
+
     fclose(file);
     return g;
 }
diff --git a/src/vector.c b/src/vector.c
index 40dc92c..9884957 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -31,7 +31,7 @@ void vector_push(Vector *v, void *element) {
 }
 
 void *vector_pop(Vector *v) {
-    if (!v->size) return NULL;
+    if (v->size == 0) return NULL;
     return v->data[--v->size];
 }