hdu 2222(AC自动机)

 参考：http://www.cppblog.com/mythit/archive/2009/04/21/80633.html
 1 /*
 2 *  AC自动机 
 3 */
 4 #include <cstdio>
 5 #include <cstdlib>
 6 #include <cstring>
 7 #include <iostream>
 8 
 9 using namespace std;
10 
11 const int N = 51;
12 const int L = 500001;
13 const int M = 1000001;
14 
15 char pat[N], str[M];
16 struct node {//节点数据 
17     int c;
18     node *prefix;
19     node *child[26];
20     node() {
21         c = 0;
22         prefix = NULL;
23         for (int i=0; i<26; ++i) child[i] = NULL;
24     }
25 }*root, *Q[L];
26 int front, rear;
27 
28 void insert(node *root, char pat[]) {//建立字典树 
29     node *p = root;
30     for (int k,i=0; pat[i]; ++i, p=p->child[k]) {
31         k = pat[i] - 'a';
32         if (!p->child[k]) p->child[k] = new node();
33     }
34     ++p->c;
35 }
36 
37 void buildAc(node *root) {//建立自动机 
38     node *p, *q;
39     root->prefix = NULL;
40     front = rear = 0;
41     Q[front++] = root;
42     while (rear < front) {
43         p = Q[rear++];
44         for (int i=0; i<26; ++i) {
45             if (p->child[i]) {
46                 if (p == root) p->child[i]->prefix = root;
47                 else {
48                     q = p->prefix;
49                     while (q!=root && !q->child[i]) q = q->prefix;
50                     if (q->child[i]) p->child[i]->prefix = q->child[i];
51                     else p->child[i]->prefix = root; 
52                 }
53                 Q[front++] = p->child[i];
54             }
55         }
56     }
57 }
58 
59 int match(node *root, char str[]) {//匹配 
60     node *p = root;
61     int cnt = 0;
62     for (int k,i=0; str[i]; ++i) {
63         k = str[i] - 'a';
64         while (!p->child[k] && p!=root) p = p->prefix;
65         p = p->child[k];
66         if (p==NULL) p = root;
67         node *tmp = p;
68         while (tmp!=root && tmp->c) {
69             cnt += tmp->c;
70             tmp->c = 0;
71             tmp = tmp->prefix;
72         }
73     }
74     return cnt;
75 }
76 
77 int main() {
78     int t;
79     scanf ("%d", &t);
80     while (t--) {
81         int n;
82         scanf ("%d", &n);
83         root = new node();
84         while (n--) scanf ("%s", pat), insert(root, pat);
85         scanf ("%s", str);
86         buildAc(root);
87         printf ("%d\n", match(root, str));
88     }
89     return 0;
90 }
posted on 2012-05-09 13:03 Try86 阅读(190) 评论(0) 收藏举报