AC自动机

#include <iostream>#define KIND 26#define STR_MAX 1000class AC_automation{struct tri_node{tri_node* fail;tri_node* next[26];bool flag;tri_node(){fail=nullptr;for(int i=0;i!=26;i++){next[i]=nullptr;}flag=false;}};typedef tri_node node_t;public:AC_automation(){root_=new node_t();}void insert_word(char* s){size_t len=strlen(s);size_t idx(0);node_t* p=root_;node_t* temp(nullptr);for (int i= 0; i != len ; i++){idx=s[i]-'a';if(p->next[idx]==nullptr){temp=new node_t();p->next[idx]=temp;}p=p->next[idx];}p->flag=true;}size_t search(char* s){int len=strlen(s);if(abs(len)>STR_MAX){return 0;}node_t * p=root_;size_t idx(0);size_t cnt(0);for(int i=0;i!=len;i++){idx=s[i]-'a';while(p->next[idx]==NULL&&p!=root_){p=p->fail;}p=p->next[idx];if(p==nullptr){p=root_;}node_t *temp=p; while(temp!=root_ && temp->flag==true){ cnt++; temp->flag=false; temp=temp->fail; } }return cnt;}~AC_automation(){clear_trie(root_);}public:void build_ac_tree(){node_t* queue[1000];memset(queue,0,sizeof(node_t*)*1000);size_t head=NULL,tail=NULL;queue[tail++]=root_;root_->fail=nullptr;node_t* p(nullptr);node_t* temp(nullptr);while(head!=tail){p=queue[head++];for(int i=0;i!=26;i++){if(p->next[i]!=nullptr){if(p==root_){p->next[i]->fail=root_;}else{temp=p->fail;while (temp!=NULL){if(temp->next[i]!=NULL){p->next[i]->fail=temp->next[i];break;}temp=temp->fail;}    if(temp==NULL) p->next[i]->fail=root_;}queue[tail++]=p->next[i];}}}}void clear_trie(node_t* node){if(node==nullptr){return;}for(int i=0;i!=26;i++){clear_trie(node->next[i]);}delete node;}private:node_t* root_;};int main(){std::cout<<"ac_mation"<<std::endl;char str[]="asherdsfggsoap";char word1[]="her";char word3[]="he";char word2[]="gsoap";AC_automation ac_auto;ac_auto.insert_word(word1);ac_auto.insert_word(word2);ac_auto.insert_word(word3);ac_auto.build_ac_tree();size_t res= ac_auto.search(str);std::cout<<res<<std::endl;getchar();}