【HDOJ】2222 Keywords Search

AC自动机基础题。

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cstdlib>
  5 #include <queue>
  6 using namespace std;
  7
  8 #define MAXL  1000005
  9 #define TRIEN 26
 10
 11 char des[MAXL], src[55];
 12
 13 typedef struct Trie {
 14     int n;
 15     Trie *fail;
 16     Trie *next[TRIEN];
 17     Trie () {
 18         n = 0;
 19         fail = NULL;
 20         memset(next, 0, sizeof(next));
 21     }
 22 } Trie;
 23
 24 Trie *root;
 25 int n;
 26
 27 void create(char str[]) {
 28     int i=0, id;
 29     Trie *p = root, *q;
 30
 31     while (str[i]) {
 32         id = str[i] - ‘a‘;
 33         ++i;
 34         if (p->next[id] == NULL) {
 35             q = new Trie();
 36             p->next[id] = q;
 37         }
 38         p = p->next[id];
 39     }
 40     p->n++;
 41 }
 42
 43 void build_fail() {
 44     int i;
 45     Trie *p, *q;
 46     queue<Trie *> que;
 47
 48     for (i=0; i<TRIEN; ++i) {
 49         if (root->next[i]) {
 50             root->next[i]->fail = root;
 51             que.push(root->next[i]);
 52         }
 53     }
 54
 55     while (!que.empty()) {
 56         p = que.front();
 57         que.pop();
 58         for (i=0; i<TRIEN; ++i) {
 59             if (p->next[i]) {
 60                 q = p->fail;
 61                 while (q != NULL) {
 62                     if (q->next[i]) {
 63                         p->next[i]->fail = q->next[i];
 64                         break;
 65                     }
 66                     q = q->fail;
 67                 }
 68                 if (q == NULL)
 69                     p->next[i]->fail = root;
 70                 que.push(p->next[i]);
 71             }
 72         }
 73     }
 74 }
 75
 76 void search() {
 77     int i = 0, id;
 78     Trie *p = root, *tmp;
 79
 80     n = 0;
 81
 82     while (des[i]) {
 83         id = des[i] - ‘a‘;
 84         ++i;
 85         while (p->next[id]==NULL && p!=root)
 86             p = p->fail;
 87         p = p->next[id];
 88         if (p == NULL)
 89             p = root;
 90         tmp = p;
 91         while (tmp != root) {
 92             n += tmp->n;
 93             tmp->n = 0;
 94             tmp = tmp->fail;
 95         }
 96     }
 97 }
 98
 99 void del(Trie *t) {
100     if (t == NULL)
101         return ;
102     for (int i=0; i<TRIEN; ++i)
103         del(t->next[i]);
104     free(t);
105 }
106
107 int main() {
108     int case_n;
109
110     scanf("%d", &case_n);
111     while (case_n--) {
112         scanf("%d", &n);
113         root = new Trie();
114         while (n--) {
115             scanf("%s", src);
116             create(src);
117         }
118         scanf("%s", des);
119         build_fail();
120         search();
121         printf("%d\n", n);
122         del(root);
123     }
124
125     return 0;
126 }

【HDOJ】2222 Keywords Search