无向图割点搜索C语言

  这个用来找到一个无向图中的所有割点,实现方式从简,例程正确.

  这个算法,对有向图是行不通的.

  通过一次深度优先搜索计算number[], 而后一趟后序遍历计算low[]来实现.

  说真的,我是基本不懂.代码还是写出来了,有点印象,日后好也有个参考.

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/*9-21-12-23-08.55.c -- 第九章第二十一题*/#include <stdio.h>#include "new_adjacenty_list.h"#define SIZE (7)/*Global variable*/char parent[SIZE] ;int visited[SIZE], number[SIZE], low[SIZE], counter = 1, root ;int main (void) ;void build_graph (Adjacenty_List * const padj, Hash_Table * const pht) ;void find_art (const Adjacenty_List * const padj, const Hash_Table * const pht, const int v) ;int min (const int val1, const int val2) ;int main (void){Adjacenty_List adj ;Hash_Table ht ;int i, size = SIZE ;Initialize_A (&adj, size) ;Initialize_H (&ht, size * 2) ;build_graph (&adj, &ht) ;for (i = 0, size = SIZE; i < size; i++)visited[i] = FALSE ;root = 0 ;find_art (&adj, &ht, root) ;Release_A (&adj) ;Release_H (&ht) ;return 0 ;}void build_graph (Adjacenty_List * const padj, Hash_Table * const pht){InitializeALine_A (padj, pht, 0, 'a', 0, 4, 'b', 0, 'd', 0) ;InitializeALine_A (padj, pht, 1, 'b', 0, 4, 'a', 0, 'c', 0) ;InitializeALine_A (padj, pht, 2, 'c', 0, 6, 'b', 0, 'd', 0, 'g', 0) ;InitializeALine_A (padj, pht, 3, 'd', 0, 8, 'a', 0, 'c', 0, 'e', 0, 'f', 0) ;InitializeALine_A (padj, pht, 4, 'e', 0, 4, 'd', 0, 'f', 0) ;InitializeALine_A (padj, pht, 5, 'f', 0, 4, 'd', 0, 'e', 0) ;InitializeALine_A (padj, pht, 6, 'g', 0, 2, 'c', 0) ;}void find_art (const Adjacenty_List * const padj, const Hash_Table * const pht, const int v){Adjoin_To_Vertex * scan ;int w ;visited[v] = TRUE ;low[v] = number[v] = counter++ ;scan = (*padj) -> list[v].adjoin_to ;while (scan){w = (*pht) -> lists[scan -> hash_value].index_in_adjacenty_list ;/*Forward edge*/if (FALSE == visited[w]){parent[w] = (*pht) -> lists[v].name ;find_art (padj, pht, w) ;if (low[w] >= number[v] && v != root)printf ("%c is an articulation point./n", (*pht) -> lists[(*padj) -> list[v].hash_value].name) ;low[v] = min (low[v], low[w]) ;}/*Back edge*/else if (parent[v] != (*pht) ->lists[w].name)low[v] = min (low[v], number[w]) ;scan = scan -> next ;}}int min (const int val1, const int val2){return val1 > val2 ? val2 : val1 ;}