HDU 2222 Keywords Search(AC自动机)

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第一道AC自动机留念,HDU第500题留念。

学习了Just Me牛的代码风格。

#include <cstdio>#include <queue>#include <cstdlib>using namespace std;const int maxn=1e6+5;char s[maxn];struct Trie{    int count;    Trie *fail, *next[26];    Trie()    {        count=0;        for(int i=0 ; i<26 ; i++ )            next[i] = NULL;        fail = NULL;    }};Trie *root;void insert(char *s){    Trie *p = root;    for(int i = 0 ; s[i] ; i++)    {        int id = s[i]-'a';        if(p -> next[id] == NULL)            p -> next[id]= new Trie();        p = p -> next[id];    }    p->count++;}void Build_AC(){    queue<Trie *>q;    q.push(root);    while(!q.empty())    {        Trie *p = q.front();        q.pop();        for(int i = 0; i < 26 ;i++)            if(p -> next[i] != NULL){            if(p == root)                p ->next[i] ->fail = root;            else            {                Trie *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;            }            q.push(p ->next[i]);        }    }}int AC(char *s){    Build_AC();    Trie *p=root;    int ret=0,index;    for(int i = 0; s[i] ; i++ ){        index = s[i]-'a';        while(p != root && p -> next[index] == NULL)            p = p -> fail;        p = p -> next[index];        if( p == NULL)        {            p = root;            continue;        }        Trie *temp=p;        while(temp != root && temp -> count != 0)        {            ret += temp -> count;            temp -> count = 0 ;            temp = temp -> fail;        }    }    return ret;}void deal(Trie *T){    for(int i = 0 ; i<26 ; i++)        if(T->next[i] != NULL)            deal(T->next[i]);    free(T);}int main(){    int T,n;    scanf("%d", &T);    while( T-- )    {        scanf("%d",&n);        root=new Trie();        getchar();        while(n--){            scanf("%s",s);            insert(s);        }        scanf("%s",s);        printf("%d\n",AC(s));

        deal(root);    }    return 0;}