BUNOJ 11552 Dominating Patterns

点击打开链接bnuoj11552

思路：AC自动机模板题
分析：
1 先对n个模板串构造trie树并且求出失配边
2 然后在文本串上面查找，找到是单词节点就把当前的单词个数加1，最后枚举输出即可。

代码：

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;

#define MAXN 1000010
#define MAX 200
#define N 30

char text[MAXN];
char words[MAX][MAX];
int vis[MAX];
int n , cnt;

struct Node{
   Node *next;
   Node *child[N];
   int number;
};
Node node[MAX*MAX];
Node *root;
queue<Node*>q;

/*字典树的空间分配*/
Node* newNode(){
   node[cnt].next = NULL;
   node[cnt].number = 0;
   for(int i = 0 ; i < N ; i++)
      node[cnt].child[i] = NULL;
   return &node[cnt++];
}

/*单词插入字典树*/
void insert(char *str , int x){
   int len = strlen(str);
   Node *p = root;
   
   for(int i = 0 ; i < len ; i++){
     int num = str[i]-'a';
     if(p->child[num] == NULL)
       p->child[num] = newNode();
     p = p->child[num];
   }
   p->number = x;
}

/*求失配边*/
void getNext(){
    while(!q.empty())
        q.pop();
    q.push(root);
    root->next = NULL;

    while(!q.empty()){
        Node *p = q.front();
        q.pop();

        for(int i = 0 ; i < N ;  i++){
           if(p->child[i] != NULL){
             q.push(p->child[i]);
             Node *tmp = p->next;
             while(tmp){
                if(tmp->child[i]){
                  p->child[i]->next = tmp->child[i];
                  break;
                }
                tmp = tmp->next;
             }
             if(tmp == NULL)
                p->child[i]->next = root;
           }
        }
    }
}

int find(){
   int len = strlen(text);
   int Max = 0;
   Node *p = root;
   
   for(int i = 0 ; i < len ; i++){
      int num = text[i]-'a';
      while(p != root && p->child[num] == NULL)
          p = p->next;
      if(p->child[num] != NULL){
        p = p->child[num];
        Node *tmp = p;
        while(tmp != NULL){
           if(tmp->number){
             vis[tmp->number]++;
             Max = max(Max , vis[tmp->number]);
           }
           tmp = tmp->next;
        }
      }
   }
   return Max;
}

/*输出*/
void output(int x){
   printf("%d\n" , x);
   for(int i = 1 ; i <= n ; i++){
      if(vis[i] == x)
        printf("%s\n" , words[i]);    
   } 
}

int main(){
   while(scanf("%d" , &n) && n){
       cnt = 0;
       root = newNode();
       memset(vis , 0 , sizeof(vis));
       for(int i = 1 ; i <= n ; i++){
          scanf("%s" , words[i]);
          insert(words[i], i);
       } 
       scanf("%s" , text);
       getNext();
       output(find());
   }  
   return 0;
}