AC自动机

重新做了下hdu2222，结果WA。。后来发现加数据了，有重复单词，感觉这种做法真无聊。

贴下模版部分：

struct node {
    int ct;
    node *pre, *next[26];
    void init() {
        ct = 0;
        pre = 0;
        memset(next, 0, sizeof(next));
    }
};

int cnt; //节点总数
node *root, trie[500010];

node *queue[500010];

void insertStr(node *root, char *str) {
    int index, len = strlen(str);
    for(int i = 0; i < len; i++) {
        index = str[i]-'a';
        if(root->next[index] == 0) {
            root->next[index] = &trie[++cnt];
            root->next[index]->init();
        }
        root = root->next[index];
    }
    root->ct++;
}

void buildAC() {
    int head, tail;
    node *u, tmp;
    queue[0] = root;
    root->pre = root;
    head = tail = 0;
    while(head <= tail) {
        u = queue[head++];
        for(int i = 0; i < 26; i++) {
            if(u->next[i] == 0) {
                if(u == root)  u->next[i] = root;
                else  u->next[i] = u->pre->next[i];
            }
            else {
                if(u == root)  u->next[i]->pre = root;
                else  u->next[i]->pre = u->pre->next[i];
                queue[++tail] = u->next[i];
            }
        }
    }
}