算法模板の字符串处理

1、AC自动机

 1 void buildTrie(Node *root, char *str){  
 2     Node *p = root;  
 3     for(int i = 0; str[i]; ++i){  
 4         int index = str[i] - '0';  
 5         if(!p->next[index]) p->next[index] = new Node(ecnt++);  
 6         p = p->next[index];  
 7     }  
 8     p->flag = true;  
 9 }  
10      
11 void makeFair(Node *root){  
12     queue<Node*> que; que.push(root);  
13     while(!que.empty()){  
14         Node *tmp = que.front(); que.pop();  
15         for(int i = 0; i < 10; ++i){  
16             if(!tmp->next[i]) continue;  
17             if(tmp == root) tmp->next[i]->fail = root;  
18             else{  
19                 Node *p = tmp->fail;  
20                 while(p){  
21                     if(p->next[i]){  
22                         tmp->next[i]->fail = p->next[i];  
23                         break;  
24                     }  
25                     p = p->fail;  
26                 }  
27                 if(!p) tmp->next[i]->fail = root;  
28             }  
29             if(tmp->next[i]->fail->flag) tmp->next[i]->flag = true;  
30             else que.push(tmp->next[i]);  
31         }  
32     }  
33     root->fail = root;  
34 }

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