欧拉回路算法C语言

  这个东西,从研究到写完,用了18小时.是我太笨了吗?不过还好,总算是写出来了.

  收拾收拾,准备去那个城市考察一下.但愿带回真实的数据供我参考.

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/* 9-32(a)-12-29-21.48.c -- 第九章第三十二题 */ #include #include #include "new_adjacenty_list.h" #include "rqueue.h" #define SIZE (12) int g_last_path = INFINITY ; int main (void) ; void buildGraph (Adjacenty_List * const padj, Hash_Table * const pht) ; int eulerCircuit (Adjacenty_List * const padj, const Hash_Table * const pht, const int start) ; void depthFirstSearch (Adjacenty_List * const padj, const Hash_Table * const pht, Rqueue * const prq, const int index) ; int isAnOddExpectZero (const int num) ; void changeVisited (Adjoin_To_Vertex * const * const vertex, const int hash_value) ; int splice (Rqueue_Node * const * const scan_1st, Rqueue * const prq_2nd) ; int main (void) { Adjacenty_List adj ; Hash_Table ht ; int capacity = SIZE, start = 0 ; Initialize_A (&adj, capacity) ; Initialize_H (&ht, capacity * 2) ; buildGraph (&adj, &ht) ; eulerCircuit (&adj, &ht, start) ; Release_A (&adj) ; Release_H (&ht) ; return 0 ; } void buildGraph (Adjacenty_List * const padj, Hash_Table * const pht) { InitializeALine_A (padj, pht, 0, 'a', 2, 4, 'c', 0, 'd', 0) ; InitializeALine_A (padj, pht, 1, 'b', 2, 4, 'c', 0, 'h', 0) ; InitializeALine_A (padj, pht, 2, 'c', 6, 12, 'a', 0, 'b', 0, 'd', 0, 'f', 0, 'g', 0, 'i', 0) ; InitializeALine_A (padj, pht, 3, 'd', 6, 12, 'a', 0, 'c', 0, 'e', 0, 'g', 0, 'j', 0, 'k', 0) ; InitializeALine_A (padj, pht, 4, 'e', 2, 4, 'd', 0, 'j', 0) ; InitializeALine_A (padj, pht, 5, 'f', 2, 4, 'c', 0, 'i', 0) ; InitializeALine_A (padj, pht, 6, 'g', 4, 8, 'c', 0, 'd', 0, 'i', 0, 'j', 0) ; InitializeALine_A (padj, pht, 7, 'h', 2, 4, 'b', 0, 'i', 0) ; InitializeALine_A (padj, pht, 8, 'i', 6, 12, 'c', 0, 'f', 0, 'g', 0, 'h', 0, 'j', 0, 'l', 0) ; InitializeALine_A (padj, pht, 9, 'j', 6, 12, 'd', 0, 'e', 0, 'g', 0, 'i', 0, 'k', 0, 'l', 0) ; InitializeALine_A (padj, pht, 10, 'k', 2, 4, 'd', 0, 'j', 0) ; InitializeALine_A (padj, pht, 11, 'l', 2, 4, 'i', 0, 'j', 0) ; } int eulerCircuit (Adjacenty_List * const padj, const Hash_Table * const pht, const int start) { Rqueue rq_1st, rq_2nd ; Rqueue_Node * scan ; int capacity = (*padj) -> capacity, i ; if (start < 0 || start >= capacity) return 0 ; if (!Initialize_R (&rq_1st) || !Initialize_R (&rq_2nd)) return 0 ; /* Test */ for (i = 0; i < capacity; i++) { if (isAnOddExpectZero ((*padj) -> indegree[i])) return 0 ; } depthFirstSearch (padj, pht, &rq_1st, start) ; scan = rq_1st -> front ; while (scan) { if ((*padj) -> indegree[scan -> index_in_adjacenty_list]) { g_last_path = INFINITY ; depthFirstSearch (padj, pht, &rq_2nd, scan -> index_in_adjacenty_list) ; scan = scan -> next ; /* Splicing these two queues */ splice (&(rq_1st -> front), &rq_2nd) ; rq_1st -> current = rq_1st -> current + rq_2nd -> current - 1 ; rq_2nd -> front = rq_2nd -> rear = NULL ; rq_2nd -> current = 0 ; } else scan = scan -> next ; } /* Print the result */ for (scan = rq_1st -> front; scan; scan = scan -> next) printf ("%c/n", (*pht) -> lists[(*padj) -> list[scan -> index_in_adjacenty_list].hash_value].name) ; Release_R (&rq_1st) ; if (!IsEmpty_R (&rq_2nd)) Release_R (&rq_2nd) ; return 1 ; } void depthFirstSearch (Adjacenty_List * const padj, const Hash_Table * const pht, Rqueue * const prq, const int index) { Adjoin_To_Vertex * scan ; int w ; // The degree of current vertex-- if (g_last_path != INFINITY) { (*padj) -> indegree[index]-- ; // The path of from Current vertex to previous vertex should be deleted */ changeVisited (&(*padj) -> list[index].adjoin_to, (*padj) -> list[g_last_path].hash_value) ; } Insert_R (prq, index) ; scan = (*padj) -> list[index].adjoin_to ; while (scan) { /* If he degree of current vertex is 0 */ if (0 == (*padj) -> indegree[(*pht) -> lists[scan -> hash_value].index_in_adjacenty_list]) scan = scan -> next ; // Else if current vertex is previous vertex */ else if (g_last_path == (*pht) -> lists[scan -> hash_value].index_in_adjacenty_list) scan = scan -> next ; // Else if current vertex has been visited */ else if (TRUE == scan -> visited) scan = scan -> next ; else break ; } if (NULL == scan) return ; /* The degree of current vertex-- */ (*padj) -> indegree[index]-- ; /* The path of from Current vertex to objective vertex should be deleted */ changeVisited (&(*padj) -> list[index].adjoin_to, scan -> hash_value) ; g_last_path = index ; w = (*pht) -> lists[scan -> hash_value].index_in_adjacenty_list ; depthFirstSearch (padj, pht, prq, w) ; } int isAnOddExpectZero (const int num) { return 0 != num && num % 2 != 0 ; } void changeVisited (Adjoin_To_Vertex * const * const vertex, const int hash_value) { if ((*vertex) -> hash_value == hash_value) (*vertex) -> visited = TRUE ; else changeVisited (&(*vertex) -> next, hash_value) ; } int splice (Rqueue_Node * const * const scan_1st, Rqueue * const prq_2nd) { Rqueue_Node * temp ; if (*scan_1st) { if ((*scan_1st) -> next -> index_in_adjacenty_list == (*prq_2nd) -> front -> index_in_adjacenty_list) { temp = (*scan_1st) -> next ; (*scan_1st) -> next = (*prq_2nd) -> front ; (*prq_2nd) -> rear -> next = temp -> next ; free (temp) ; return 1 ; } else splice (&(*scan_1st) -> next, prq_2nd) ; } else return 0 ; }