free graph when we're done, valgrind says everything is cool. updated readme.

Author: imphasing

README

@@ -0,0 +1,17 @@
+Sudoku Solver
+=============
+
+Graph coloring based sudoku solver. Yes, I could just bruteforce it in a simpler way, but this is cooler.
+
+Accepts input from stdin, puzzles should be one line with 0s to mark blank cells, like this:
+
+    530070000600195000098000060800060003400803001700020006060000280000419005000080079 
+
+You can run the examples by building the program with make, then something like:
+
+    cat sample_easy | ./solver
+
+It will return the solved puzzle in the same format, or error out saying it cannot color the graph. Currently, this solver only supports 9x9 puzzles and will expect 81 characters to be read from stdin.
+
+
+

README.md

@@ -11,6 +11,30 @@ struct graph *create_graph()
 	return created;
 }
 
+
+void free_graph(struct graph *graph)
+{
+	struct vertex *next_vertex = graph->vertices;
+
+	while (next_vertex != NULL) {
+		struct vertex *current = next_vertex;
+		next_vertex = next_vertex->next;
+
+		struct edge *next_edge = current->edges;
+		while (next_edge != NULL) {
+			struct edge *current_edge = next_edge;
+			next_edge = next_edge->next;
+
+			free(current_edge);
+		}
+
+		free(current);
+	}
+
+	free(graph);
+}
+
+
 struct vertex *add_vertex(struct graph *graph, int num_possible, int value)
 {
 	struct vertex *next = malloc(sizeof(struct vertex));
@@ -24,6 +48,7 @@ struct vertex *add_vertex(struct graph *graph, int num_possible, int value)
 	return next;
 }
 
+
 void add_edge(struct vertex *vertex1, struct vertex *vertex2)
 {
 	struct edge *next = malloc(sizeof(struct edge));
@@ -32,6 +57,7 @@ void add_edge(struct vertex *vertex1, struct vertex *vertex2)
 	vertex1->edges = next;
 }
 
+
 void print_graph(struct graph *graph)
 {
 	int edge_count = 0;
@@ -79,10 +105,7 @@ void print_sudoku(struct graph *graph, int size)
 		printf("%d", output[index]);
 
 	printf("\n");
-}
 
-
-
-	
-	
+	free(output);
+}
 

graph.c

@@ -5,6 +5,7 @@ struct graph {
 	int vertex_index;
 };
 
+
 struct vertex {
 	int current_value;
 	int num_possible;
@@ -22,8 +23,11 @@ struct edge {
 
 
 struct graph *create_graph();
+void free_graph(struct graph *graph);
+
 struct vertex *add_vertex(struct graph *graph, int num_possible, int value);
 void add_edge(struct vertex *vertex1, struct vertex *vertex2);
+
 void print_graph(struct graph *graph);
 void print_sudoku(struct graph *graph, int size);
 

graph.h

@@ -72,7 +72,6 @@ bool color_graph(struct vertex *vertex, int num_colors)
 	int original_value = vertex->current_value;
 	int original_num = vertex->num_possible;
 
-
 	if (original_num == 1)
 		return color_graph(vertex->next, num_colors);	
 

graph_color.c

@@ -1,14 +1,2 @@
 530070000600195000098000060800060003400803001700020006060000280000419005000080079
 
-
-
-530070000
-600195000
-098000060
-800060003
-400803001
-700020006
-060000280
-000419005
-000080079
-

sample_easy

@@ -23,6 +23,7 @@ bool index_in_group(int *group, int size, int index)
 	return false;
 }
 
+
 // link a vertex at index with every other vertex in the group
 void link_vertex_with_group(int *group, int size, int index, struct vertex **vertices)
 {
@@ -61,6 +62,7 @@ void link_three_groups(struct vertex **vertices)
 	}
 }
 
+
 // link rows and columns together
 void link_cols_and_rows(struct vertex **vertices)
 {
@@ -84,6 +86,7 @@ void link_cols_and_rows(struct vertex **vertices)
 				link_vertex_with_group(current_col, 9, j, vertices);
 	}
 }
+
 
 // create graph, load up vertices and link them together in the sudoku pattern
 struct graph *load_initial()
@@ -96,7 +99,6 @@ struct graph *load_initial()
 	char *buffer = malloc(sizeof(char) * num_chars);
 	fgets(buffer, num_chars, stdin);
 
-
 	struct graph *graph = create_graph();
 	struct vertex **vertices = malloc(sizeof(void *) * num_boxes);
 
@@ -113,10 +115,12 @@ struct graph *load_initial()
 		}
 	}
 
-
 	link_three_groups(vertices);
 	link_cols_and_rows(vertices);
 
+	free(buffer);
+	free(vertices);
+
 	return graph;
 }
 
@@ -128,11 +132,11 @@ int main(int argc, char **argv)
 	color_graph(graph->vertices, 9);
 
 	if (graph_colored(graph))
-		printf("Graph is colored.\n");
+		print_sudoku(graph, 9);
 	else
-		printf("Graph is not colored.\n");
+		printf("Unable to color sudoku graph.\n");
 
-	print_sudoku(graph, 9);
+	free_graph(graph);
 
 	return 0;
 }