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/**
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* File: graph_bfs.c
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* Created Time: 2023-07-11
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* Author: NI-SW (947743645@qq.com)
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*/
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#include "graph_adjacency_list.c"
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/* 哈希表 */
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struct hashTable {
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unsigned int size;
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unsigned int *array;
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};
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typedef struct hashTable hashTable;
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/* 初始化哈希表 */
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hashTable *newHash(unsigned int size) {
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hashTable *h = (hashTable *)malloc(sizeof(hashTable));
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h->array = (unsigned int *)malloc(sizeof(unsigned int) * size);
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memset(h->array, 0, sizeof(unsigned int) * size);
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h->size = size;
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return h;
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}
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/* 标记索引过的顶点 */
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void hashMark(hashTable *h, int index) {
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h->array[index % h->size] = 1;
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}
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/* 查询顶点是否已被标记 */
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int hashQuery(hashTable *h, int index) {
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// 若顶点已被标记，则返回 0
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if (h->array[index % h->size] == 1) {
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return 0;
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} else {
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return 1;
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}
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}
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/* 释放哈希表内存 */
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void freeHash(hashTable *h) {
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free(h->array);
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free(h);
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}
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/* 队列 */
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struct queue {
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Vertex **list;
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unsigned int size;
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int head;
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int tail;
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};
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typedef struct queue queue;
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/* 初始化队列 */
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queue *newQueue(unsigned int size) {
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queue *q = (queue *)malloc(sizeof(queue));
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q->size = size;
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q->list = (Vertex **)malloc(sizeof(Vertex *) * size);
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q->head = 0;
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q->tail = 0;
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return q;
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}
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/* 入队 */
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void queuePush(queue *q, Vertex *v) {
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q->list[q->tail] = v;
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q->tail++;
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}
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/* 出队 */
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void queuePop(queue *q) {
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q->head++;
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}
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/* 队首元素 */
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Vertex *queueTop(queue *q) {
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return q->list[q->head];
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}
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/* 释放队列内存 */
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void freeQueue(queue *q) {
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free(q->list);
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free(q);
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}
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/* 广度优先遍历 */
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void graphBFS(graphAdjList *t) {
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// 初始化队列与哈希表
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queue *que = newQueue(t->size);
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hashTable *visited = newHash(t->size);
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// 将第一个元素入队
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queuePush(que, t->verticesList[0]);
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hashMark(visited, t->verticesList[0]->pos);
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printf("\n[");
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while (que->head < que->tail) {
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// 遍历该顶点的边链表，将所有与该顶点有连接的，并且未被标记的顶点入队
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Node *n = queueTop(que)->linked->head->next;
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while (n != 0) {
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// 查询哈希表，若该索引的顶点已入队，则跳过，否则入队并标记
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if (hashQuery(visited, n->val->pos) != 0) {
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queuePush(que, n->val);
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hashMark(visited, n->val->pos);
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}
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n = n->next;
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}
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// 打印队首元素
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if (que->head == que->tail - 1) {
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printf("%d]\n", queueTop(que)->val);
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} else {
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printf("%d, ", queueTop(que)->val);
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}
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// 队首元素出队
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queuePop(que);
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}
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printf("\n");
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// 释放队列与哈希表内存
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freeQueue(que);
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freeHash(visited);
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}
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int main() {
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/* 初始化无向图 */
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graphAdjList *graph = newGraphic(3);
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// 初始化顶点
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for (int i = 0; i < 10; i++) {
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addVertex(graph, i);
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}
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// 初始化边
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addEdge(graph, 0, 1);
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addEdge(graph, 0, 3);
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addEdge(graph, 1, 2);
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addEdge(graph, 1, 4);
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addEdge(graph, 2, 5);
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addEdge(graph, 3, 4);
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addEdge(graph, 3, 6);
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addEdge(graph, 4, 5);
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addEdge(graph, 4, 7);
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addEdge(graph, 5, 8);
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addEdge(graph, 6, 7);
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addEdge(graph, 7, 8);
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printf("\n初始化后，图为:\n");
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printGraph(graph);
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printf("\n广度优先遍历（BFS）顶点序列为");
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graphBFS(graph);
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return 0;
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}
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