AC自动机(trie+KMP)

AC自动机可以在线性时间内匹配多个模式串，算法思路是一个在trie上使用KMP算法
trie的讲解和AC自动机算法具体讲解(dalao的帖子)
http://www.cppblog.com/menjitianya/archive/2014/07/10/207604.html

//hdu2222
#define clr(a,x) memset(a,x,sizeof a)
struct  Aho {
    struct state {
        int next[26];
        int fail, cnt;
    }stateTable[maxn];
    int size;
    queue<int> que;
    void init() {
        while (que.size()) que.pop();
        for (int i = 0; i < maxn; i++) {
            clr(stateTable[i].next, 0);
            stateTable[i].fail = stateTable[i].cnt = 0;
        }
        size = 1;
    }
    void insert(char *s) {
        int n = strlen(s);
        int now = 0;
        for (int i = 0; i < n; i++) {
            char c = s[i];
            if (!stateTable[now].next[c - 'a'])
                stateTable[now].next[c - 'a'] = size++;
            now = stateTable[now].next[c - 'a'];
        }
        stateTable[now].cnt++;
    }
    void build() {
        stateTable[0].fail = -1;
        que.push(0);
        while (que.size()) {
            int u = que.front();
            que.pop();
            for (int i = 0; i < 26; i++) {
                if (stateTable[u].next[i]) {
                    if (u == 0) stateTable[stateTable[u].next[i]].fail = 0;
                    else {
                        int v = stateTable[u].fail;
                        while (v != -1) {
                            if (stateTable[v].next[i]) {
                                stateTable[stateTable[u].next[i]].fail = stateTable[v].next[i];
                                break;
                            }
                            v = stateTable[v].fail;
                        }
                        if (v == -1) stateTable[stateTable[u].next[i]].fail = 0;
                    }
                    que.push(stateTable[u].next[i]);
                }
            }
        }
    }

    int Get(int u) {
        int res = 0;
        while (u) {
            res = res + stateTable[u].cnt;
            stateTable[u].cnt = 0;
            u = stateTable[u].fail;
        }
        return res;
    }
    int match(char *s) {
        int n = strlen(s);
        int res = 0, now = 0;
        for (int i = 0; i < n; i++) {
            char c = s[i];
            if (stateTable[now].next[c - 'a']) {
                now = stateTable[now].next[c - 'a'];
            }
            else {
                int p = stateTable[now].fail;
                while (p != -1 && stateTable[p].next[c - 'a'] == 0) p = stateTable[p].fail;
                if (p == -1) now = 0;
                else now = stateTable[p].next[c - 'a'];
            }
            if (stateTable[now].cnt)
                res = res + Get(now);
        }
        return res;
    }
}aho;
int T;
int N;
char S[maxn];
int main() { 
    scanf("%d", &T);
    while (T--) {
        aho.init();
        scanf("%d", &N);
        for (int i = 0; i < N; i++) {
            scanf("%s", S);
            aho.insert(S);
        }
        aho.build();
        scanf("%s", S);
        printf("%d\n", aho.match(S));
    }
    return 0;
}