HDOJ 2222 AC自动机

Posted 2020-09-15 Flowersea

链接：

http://acm.hdu.edu.cn/showproblem.php?pid=2222

代码：

 31 string s, a[51];
 32 int head, tail;
 33 
 34 struct node {
 35     node *fail;
 36     node *next[26];
 37     int count;
 38     node() {
 39         fail = NULL;
 40         count = 0;
 41         rep(i, 0, 26) next[i] = NULL;
 42     }
 43 }*q[MAXN];
 44 node *root;
 45 
 46 void insert(string s) {
 47     node *p = root;
 48     int len = s.length();
 49     rep(i, 0, len) {
 50         int temp = s[i] - ‘a‘;
 51         if (p->next[temp] == NULL) p->next[temp] = new node();
 52         p = p->next[temp];
 53     }
 54     p->count++;
 55 }
 56 
 57 void build_ac() {
 58     q[tail++] = root;
 59     while (head != tail) {
 60         node *p = q[head++];
 61         node *temp = NULL;
 62         rep(i, 0, 26) if (p->next[i] != NULL) {
 63             if (p == root) p->next[i]->fail = root;
 64             else {
 65                 temp = p->fail;
 66                 while (temp != NULL) {
 67                     if (temp->next[i] != NULL) {
 68                         p->next[i]->fail = temp->next[i];
 69                         break;
 70                     }
 71                     temp = temp->fail;
 72                 }
 73                 if (temp == NULL) p->next[i]->fail = root;
 74             }
 75             q[tail++] = p->next[i];
 76         }
 77     }
 78 }
 79 
 80 int query() {
 81     int res = 0;
 82     node *p = root;
 83     int len = s.length();
 84     rep(i, 0, len) {
 85         int index = s[i] - ‘a‘;
 86         while (p->next[index] == NULL && p != root) p = p->fail;
 87         p = p->next[index];
 88         if (p == NULL) p = root;
 89         node *temp = p;
 90         while (temp != root && temp->count != -1) {
 91             res += temp->count;
 92             temp->count = -1;
 93             temp = temp->fail;
 94          }
 95     }
 96     return res;
 97 }
 98 
 99 int main() {
100     ios::sync_with_stdio(false), cin.tie(0);
101     int T;
102     cin >> T;
103     while (T--) {
104         head = tail = 0;
105         root = new node();
106         int n;
107         cin >> n;
108         while (n--) {
109             cin >> s;
110             insert(s);
111         }
112         build_ac();
113         cin >> s;
114         cout << query() << endl;
115     }
116     return 0;
117 }