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#include <stdio.h>
#include <stdlib.h>
#define COL_WHITE 0
#define COL_GRAY 1
#define COL_BLACK 2
typedef struct list_node_t_struct {
struct list_node_t_struct *next;
void *val;
} list_node_t;
typedef struct vertex_struct {
char ref;
int color;
int dist;
struct vertex_struct *p;
list_node_t *adj;
} vertex_t;
vertex_t *create_vertex(char ref)
{
// Get some space TODO check for null
vertex_t *v = malloc(sizeof(vertex_t));
// Set values
v->ref = ref;
v->color = COL_WHITE;
v->dist = -1;
v->p = NULL;
v->adj = NULL;
}
vertex_t *add_adj(vertex_t *v, vertex_t *add)
{
list_node_t *oldN = v->adj;
// Create new list node
list_node_t *n = malloc(sizeof(list_node_t));
n->val = add;
n->next = oldN;
v->adj = n;
return add;
}
void print_adj(vertex_t *v)
{
list_node_t *n = v->adj;
printf("[ ");
while (n) {
printf("%c ", *((char *)n->val));
n = n->next;
}
printf("]\n");
}
vertex_t *vertexes[128];
void add_edge(char a, char b)
{
// Does a exists
if (vertexes[a] == NULL) {
vertexes[a] = create_vertex(a);
}
// What about b
if (vertexes[b] == NULL) {
vertexes[b] = create_vertex(b);
}
// Add edge
add_adj(vertexes[a], vertexes[b]);
}
typedef struct {
unsigned int len;
list_node_t *in;
list_node_t *out;
} queue_t;
void enqueue(queue_t *q, vertex_t *v)
{
list_node_t *n = malloc(sizeof(list_node_t));
n->val = v;
// Add at end
list_node_t *old = q->in;
q->in = n;
if (old) {
old->next = n;
}
// Make sure we have an out
if (q->out == NULL) {
q->out = n;
}
q->len++;
}
vertex_t *dequeue(queue_t *q)
{
list_node_t *n = q->out;
if (n == NULL) {
return NULL;
}
vertex_t *v = (vertex_t *)n->val;
// Move out forward
q->out = n->next;
q->len--;
// Free node and return
free(n);
return v;
}
void bfs(vertex_t *s)
{
queue_t q = { 0, NULL, NULL };
enqueue(&q, s);
s->dist = 0;
while (q.len) {
vertex_t *u = dequeue(&q);
list_node_t *n = u->adj;
while (n) {
vertex_t *v = (vertex_t *)n->val;
if (v->color == COL_WHITE) {
v->color = COL_GRAY;
v->dist = u->dist + 1;
v->p = u;
enqueue(&q, v);
}
n = n->next;
}
u->color = COL_BLACK;
}
}
int main()
{
add_edge('s', 'd'); // S
add_edge('s', 'c');
add_edge('s', 'a');
add_edge('d', 'e'); // D
add_edge('d', 'c');
add_edge('e', 'g'); // E
add_edge('e', 'f');
add_edge('c', 's'); // C
add_edge('c', 'g');
add_edge('g', 'f'); // G
//print_adj(vertexes['d']);
bfs(vertexes['s']);
char c;
while ((c = getchar()) != EOF) {
if (vertexes[c] != NULL) {
print_adj(vertexes[c]);
printf("%d\n", vertexes[c]->dist);
} else if (c == 10) {
} else {
printf("Not found\n");
}
}
}
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