Finished DFS for directed graphs.

ramkumarkb · Jul 31, 2016 · df2a60e · df2a60e
1 parent a16d837
commit df2a60e
Show file tree

Hide file tree

Showing 3 changed files with 106 additions and 15 deletions.
diff --git a/graphs/graphs.c b/graphs/graphs.c
@@ -12,7 +12,7 @@ UndirectedGraph* ugraph_create(const int v) {
     g->adjacency_list[i] = malloc(sizeof(struct neighbors));
     assert(g->adjacency_list[i]);
 
-    g->adjacency_list[i]->count = 0;
+    g->adjacency_list[i]->length = 0;
     g->adjacency_list[i]->capacity = 0;
   }
 
@@ -39,36 +39,103 @@ void ugraph_add_edge(UndirectedGraph* g, const int src, const int dest) {
 
 void _ugraph_append_edge(UndirectedGraph* g, const int src, const int dest) {
   // resizes array if needed
-  if (g->adjacency_list[src]->count == g->adjacency_list[src]->capacity) {
+  if (g->adjacency_list[src]->length == g->adjacency_list[src]->capacity) {
     g->adjacency_list[src]->capacity = g->adjacency_list[src]->capacity * 2 + 1;
 
-    g->adjacency_list[src] = realloc(g->adjacency_list[src], sizeof(struct neighbors) + sizeof(int) * g->adjacency_list[src]->capacity);
+    g->adjacency_list[src] =
+        realloc(g->adjacency_list[src],
+                sizeof(struct neighbors) +
+                    sizeof(int) * g->adjacency_list[src]->capacity);
   }
 
-  g->adjacency_list[src]->list[g->adjacency_list[src]->count++] = dest;
+  g->adjacency_list[src]->list[g->adjacency_list[src]->length++] = dest;
 
   g->e++;
 }
 
-void ugraph_print_debug(UndirectedGraph* g) {
+void ugraph_print_dfs(UndirectedGraph* g) {
   int visited[g->v];
   memset(visited, 0, sizeof(visited));
 
+  // will find all vertices if graph is connected
   ugraph_dfs(g, visited, 0);
 }
 
 void ugraph_dfs(UndirectedGraph* g, int visited[], const int vertex) {
   visited[vertex] = 1;
   printf("%d -> ", vertex);
 
-  for (int e = 0; e < g->adjacency_list[vertex]->count; ++e) {
+  for (int e = 0; e < g->adjacency_list[vertex]->length; ++e) {
     int u = g->adjacency_list[vertex]->list[e];
 
     if (visited[u] == 0) {
       ugraph_dfs(g, visited, u);
     }
   }
+}
+
+DirectedGraph* digraph_create(const int v) {
+  DirectedGraph* g =
+      malloc(sizeof(DirectedGraph) + sizeof(struct targets*) * v);
+  assert(g);
+
+  g->v = v;
+  g->e = 0;
+
+  for (int i = 0; i < v; ++i) {
+    g->adjacency_list[i] = malloc(sizeof(struct targets));
+    assert(g->adjacency_list[i]);
+
+    g->adjacency_list[i]->length = 0;
+    g->adjacency_list[i]->capacity = 0;
+  }
+
+  return g;
+}
 
-  putchar('\n');
+void digraph_destroy(DirectedGraph* g) {
+  for (int i = 0; i < g->v; ++i) {
+    free(g->adjacency_list[i]);
+  }
+  free(g);
 }
 
+void digraph_add_edge(DirectedGraph* g, const int src, const int dest) {
+  assert(src != dest);
+  assert(src >= 0 && src < g->v);
+  assert(dest >= 0 && dest < g->v);
+
+  if (g->adjacency_list[src]->length == g->adjacency_list[src]->capacity) {
+    g->adjacency_list[src]->capacity = g->adjacency_list[src]->capacity * 2 + 1;
+    g->adjacency_list[src] =
+        realloc(g->adjacency_list[src],
+                sizeof(struct targets) +
+                    sizeof(int) * g->adjacency_list[src]->capacity);
+  }
+
+  g->adjacency_list[src]->list[g->adjacency_list[src]->length++] = dest;
+  g->e++;
+}
+
+void digraph_print_dfs(DirectedGraph* g) {
+  int visited[g->v];
+  memset(visited, 0, sizeof(visited));
+
+  for (int v = 0; v < g->v; ++v) {
+    digraph_dfs(g, visited, v);
+  }
+}
+
+void digraph_dfs(DirectedGraph* g, int visited[], const int vertex) {
+  visited[vertex] = 1;
+
+  printf("\n%d: ", vertex);
+
+  for (int i = 0; i < g->adjacency_list[vertex]->length; ++i) {
+    int adj_vertex = g->adjacency_list[vertex]->list[i];
+    if (visited[adj_vertex] == 0) {
+      printf("\t%d -> %d, ", vertex, adj_vertex);
+      digraph_dfs(g, visited, adj_vertex);
+    }
+  }
+}
diff --git a/graphs/graphs.h b/graphs/graphs.h
@@ -11,7 +11,7 @@ typedef struct {
   int e; /* edge count */
 
   struct neighbors {
-    int count;
+    int length;
     int capacity;
     int list[];
   } * adjacency_list[];
@@ -23,7 +23,7 @@ typedef struct {
   int e; /* edge count */
 
   struct targets {
-    int count;
+    int length;
     int capacity;
     int list[];
   } * adjacency_list[];
@@ -38,16 +38,18 @@ void ugraph_add_edge(UndirectedGraph* g, const int src, const int dest);
 
 void _ugraph_append_edge(UndirectedGraph* g, const int src, const int dest);
 
-void ugraph_print_debug(UndirectedGraph* g);
+void ugraph_print_dfs(UndirectedGraph* g);
 
 void ugraph_dfs(UndirectedGraph* g, int visited[], const int vertex);
 
-DirectedGraph* digraph_create(int v);
+DirectedGraph* digraph_create(const int v);
 
 void digraph_destroy(DirectedGraph* g);
 
 void digraph_add_edge(DirectedGraph* g, const int src, const int dest);
 
-void digraph_print_debug(DirectedGraph* g);
+void digraph_print_dfs(DirectedGraph* g);
+
+void digraph_dfs(DirectedGraph* g, int visited[], const int vertex);
 
 #endif  // PROJECT_GRAPHS_H
diff --git a/graphs/main.c b/graphs/main.c
@@ -1,10 +1,14 @@
+#include <stdio.h>
 #include "graphs.h"
 
 int main(int argc, char* argv[]) {
 
-  const int vertices = 9;
+  const int u_vertices = 9;
+  const int d_vertices = 9;
 
-  UndirectedGraph* g = ugraph_create(vertices);
+  UndirectedGraph* g = ugraph_create(u_vertices);
+
+  printf("Undirected graph with %d vertices:\n", u_vertices);
 
   ugraph_add_edge(g, 0, 1);
   ugraph_add_edge(g, 1, 2);
@@ -19,9 +23,27 @@ int main(int argc, char* argv[]) {
   ugraph_add_edge(g, 6, 8);
   ugraph_add_edge(g, 7, 8);
 
-  ugraph_print_debug(g);
+  ugraph_print_dfs(g);
 
   ugraph_destroy(g);
 
+  printf("\n\nDirected graph with %d vertices:\n", d_vertices);
+
+  DirectedGraph* dg = digraph_create(d_vertices);
+
+  digraph_add_edge(dg, 0, 1);
+  digraph_add_edge(dg, 0, 5);
+  digraph_add_edge(dg, 1, 2);
+  digraph_add_edge(dg, 2, 4);
+  digraph_add_edge(dg, 2, 6);
+  digraph_add_edge(dg, 3, 2);
+  digraph_add_edge(dg, 6, 5);
+  digraph_add_edge(dg, 5, 8);
+  digraph_add_edge(dg, 7, 5);
+
+  digraph_print_dfs(dg);
+
+  digraph_destroy(dg);
+
   return 0;
 }