Created
September 20, 2017 09:26
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Recursive example of a BFS in C
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| #include <stdlib.h> | |
| #include <assert.h> | |
| #include <stdio.h> | |
| struct queue { | |
| size_t cap, start, size; | |
| int store[0]; | |
| }; | |
| struct queue* new_queue(size_t cap) | |
| { | |
| struct queue *q = malloc(sizeof (struct queue) + cap * sizeof (int)); | |
| q->cap = cap; | |
| q->start = q->size = 0; | |
| return q; | |
| } | |
| void push(struct queue *q, int x) | |
| { | |
| assert(q->size < q->cap); | |
| q->store[(q->start + q->size) % q->cap] = x; | |
| q->size += 1; | |
| } | |
| int pop(struct queue *q) | |
| { | |
| assert(q->size); | |
| int x = q->store[q->start]; | |
| q->start += 1; | |
| q->size -= 1; | |
| return x; | |
| } | |
| int edges[4][4] = { | |
| {0, 1, 1, 0}, | |
| {1, 0, 0, 1}, | |
| {1, 0, 0, 0}, | |
| {0, 1, 0, 0} | |
| }; | |
| int vertices = 4; | |
| int set[4] = {0}; | |
| int recbfs(int i, struct queue *q) | |
| { | |
| printf("%d ", i); // display vertices as soon as they are visited | |
| for (int j = 0; j < vertices; j++) { | |
| if (i != j && edges[i][j] && set[j] == 0) { | |
| set[j] = 1; | |
| push(q, j); | |
| } | |
| } | |
| if (q->size == 0) | |
| return 1; | |
| int next = pop(q); | |
| return recbfs(next, q); | |
| } | |
| int main() | |
| { | |
| struct queue *q = new_queue(vertices); | |
| set[0] = 1; | |
| recbfs(0, q); | |
| free(q); | |
| return 0; | |
| } |
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