hdu3695 AC自动机优化

题目链接：http://icpc.njust.edu.cn/Problem/Hdu/3695/

不加last指针的AC自动机会T，原因是他费了很多功夫在跳转上，而last指针是直接直到跳转的终止位置，直接跳转到终止位置上，所以只有一次跳转。未优化的fail指针最坏的情况下复杂度是O(|S|*|T|)，其中|S|是模式串长度的均值，|T|是文本串的 长度。

代码如下：

 #include<bits/stdc++.h>
 using namespace std;
 #define LL long long
 #define ULL unsigned LL
 #define fi first
 #define se second
 #define lson l,m,rt<<1
 #define rson m+1,r,rt<<1|1
 #define max3(a,b,c) max(a,max(b,c))
 #define min3(a,b,c) min(a,min(b,c))
 const int INF = 0x3f3f3f3f;
 const LL mod = 1e9+;
 typedef pair<int,int> pll;
 const int N = 1e6+;
 int tot = ;
 char str[N*], tmp[N*];
 int trie[N*][], cnt[N*], fair[N*];
 void init(){
     for(int i = ; i < tot; i++){
         for(int j = ; j < ; j++)
             trie[i][j] = ;
     }
     tot = ;
 }
 void Insert(){
     int rt = , len = strlen(str);
     for(int i = ; i < len; i++){
         int id = str[i] - 'A';
         if(!trie[rt][id]) {
             cnt[tot] = ;
             fair[tot] = ;
             trie[rt][id] = tot++;
         }
         rt = trie[rt][id];
     }
     cnt[rt]++;
 }
 void Build_tree(){
     queue<int> q;
     q.push();
     int p;
     while(!q.empty()){
         int tmp = q.front();
         q.pop();
         for(int j = ; j < ; j++){
             if(trie[tmp][j]){
                 if(tmp == )
                     fair[trie[tmp][j]] = ;
                 else {
                     p = fair[tmp];
                     while(p){
                         if(trie[p][j]){
                             fair[trie[tmp][j]] = trie[p][j];
                             break;
                         }
                         else p = fair[p];
                     }
                     if(!p) fair[trie[tmp][j]] = ;
                 }
                 q.push(trie[tmp][j]);
             }
         }
     }
 }
 int Find(int len){
     int ret = , rt = ;
     for(int i = ; i < len; i++){
         int id = str[i] - 'A';
         while(rt !=   && !trie[rt][id]) rt = fair[rt];;
         if(trie[rt][id]) rt = trie[rt][id];
         int p = rt;
         while(p != ){
             if(cnt[p] >= ){
                 ret += cnt[p];
                 cnt[p] = -;
             }
             else break;
             p = fair[p];
         }
     }
     rt = ;
     for(int i = len - ; i >= ; i--){
         int id = str[i] - 'A';
         while(rt !=   && !trie[rt][id]) rt = fair[rt];
         if(trie[rt][id]) rt = trie[rt][id];
         int p = rt;
         while(p != ){
             if(cnt[p] >= ){
                 ret += cnt[p];
                 cnt[p] = -;
             }
             else break;
             p = fair[p];
         }
     }
     return ret;
 }
 int main(){
     int t;
     scanf("%d", &t);
     while(t--){
         int n;
         init();
         scanf("%d", &n);
         while(n--){
             scanf("%s", str);
             Insert();
         }
         Build_tree();
         scanf("%s", tmp);
         int len = strlen(tmp);
         int ccc = ;
         for(int i = ; i < len; i++){
             if(tmp[i] != '['){
                 str[ccc++] = tmp[i];
             }
             else {
                 int _c = ;
                 i++;
                 while(isdigit(tmp[i]))
                     _c = _c * + (int)(tmp[i]-''), i++;
                 while(_c--)
                     str[ccc++] = tmp[i];
                 i++;
             }
         }
         printf("%d\n", Find(ccc));
     }
     return ;
 }