hdu 2222 Keywords Search

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#define MAX 1000000
using namespace std;
struct Trie {
    Trie *Next[26],*Fail;
    int sum;
    Trie() {
        for(int i = 0;i < 26;i ++) {
            Next[i] = NULL;
        }
        Fail = NULL;
        sum = 0;
    }
}*root;
void Insert_Str(char *s) {///字符串插入到字典树中
   Trie *r = root;
   int i = -1;
   while(s[++ i]) {
       int d = s[i] - ‘a‘;
       if(r -> Next[d] == NULL) {
           r -> Next[d] = new Trie();
       }
       r = r -> Next[d];
   }
   r -> sum ++;///结尾加1
}
void Build_Fail() {///通过父结点的Fail更新子结点的Fail
    Trie *node,*temp;
    queue<Trie *> q;
    q.push(root);
    while(!q.empty()) {
        node = q.front();
        q.pop();
        for(int i = 0;i < 26;i ++) {
            if(node -> Next[i]) {///第i个儿子存在
                temp = node -> Fail;///temp赋值当前节点的Fail
                while(temp) {
                    if(temp -> Next[i]) {
                        node -> Next[i] -> Fail = temp -> Next[i];
                        break;
                    }
                    temp = temp -> Fail;
                }
                if(temp == NULL) {///没找到或者本来就是根节点
                    node -> Next[i] -> Fail = root;
                }
                q.push(node -> Next[i]);
            }
        }
    }
}
int Ac_automation(char *s) {
    int i = -1,ans = 0;
    Trie *node = root,*temp;
    while(s[++ i]) {
        int d = s[i] - ‘a‘;
        while(node != root && node -> Next[d] == NULL) node = node -> Fail;///如果没有匹配的子结点 就找它的Fail看看有没有匹配的子结点
        if(node -> Next[d]) node = node -> Next[d];
        temp = node;
        while(temp && temp -> sum >= 0) {
            ans += temp -> sum;
            temp -> sum = -1;///出现了  再出现时不再计算
            temp = temp -> Fail;///找最长后缀
        }
    }
    return ans;
}
int main() {
    int t,n;
    char tr[50],s[MAX];
    scanf("%d",&t);
    while(t --) {
        root = new Trie();
        scanf("%d",&n);
        for(int i = 0;i < n;i ++) {
            scanf("%s",tr);
            Insert_Str(tr);
        }
        Build_Fail();
        scanf("%s",s);
        printf("%d\n",Ac_automation(s));
    }
}