AC自动机模板（c++版和java版）

        这是我第一次写博客，可能整理的不好，请大家见谅。

        先发一些我最近在刷的AC自动机的题，模版题我就不发了。。初学的话，可以看一下

AC自动机算法 - 飘过的小牛 - 博客频道 - CSDN.NET

的博客。

        另外贴一个模版题的代码吧

        hdu2222 Keywords Search

//AC自动机#include<stdio.h>#include<string.h>#include<algorithm>#include<queue>using namespace std ;const int maxn = 5555555 ;class AC_auto{private :    int tot , fail[maxn] , val[maxn] , c[26][maxn] ;    queue<int> Q ;    int new_node ()    {        int i ;        fail[tot] = val[tot] = 0 ;        for ( i = 0 ; i < 26 ; i ++ ) c[i][tot] = 0 ;        return tot ++ ;    }public :    void init ()    {        tot = 0 ; new_node () ;        while ( !Q.empty () ) Q.pop () ;    }    void insert ( char *s )    {        int now = 0 ;        for ( ; *s ; s ++ )        {            int k = *s - 'a' ;            if ( !c[k][now] ) c[k][now] = new_node () ;            now = c[k][now] ;        }        val[now] ++ ;    }    void get_fail ()    {        int i , u = 0 , j , e ;        for ( i = 0 ; i < 26 ; i ++ ) if ( c[i][u] ) Q.push ( c[i][u] ) ;        while ( !Q.empty () )        {            u = Q.front () ;            Q.pop () ;            for ( i = 0 ; i < 26 ; i ++ )            {                if ( !c[i][u] )                {                    c[i][u] = c[i][fail[u]] ;                    continue ;                }                e = c[i][u] ;                j = fail[u] ;                fail[e] = c[i][j] ;                Q.push ( e ) ;            }        }    }    int work ( char *s )    {        int u = 0 , i , e , ret = 0 ;        for ( ; *s ; s ++ )        {            int k = *s - 'a' ;            u = c[k][u] ;            e = u ;            while ( e )            {                if ( val[e] )                {                    ret += val[e] ;                    val[e] = 0 ;                }                e = fail[e] ;            }        }        return ret ;    }} ac ;char s[maxn] ;int main (){    int cas , n ;    scanf ( "%d" , &cas ) ;    while ( cas -- )    {        scanf ( "%d" , &n ) ;        ac.init () ;        while ( n -- )        {            scanf ( "%s" , s ) ;            ac.insert ( s ) ;        }        ac.get_fail () ;        scanf ( "%s" , s ) ;        printf ( "%d\n" , ac.work ( s ) ) ;    }}

再来个java版的ac自动机模板

import java.io.*;import java.util.*;import java.math.*;class Que {int[] q = new int[1111111];int tail, star;void init() {star = 1;tail = 0;}void push(int v) {q[++tail] = v;}void pop() {star++;}int front() {return q[star];}int empty() {if (star > tail)return 1;elsereturn 0;}}class AC_auto {int tot;int[][] c = new int[26][255555];int[] fail = new int[255555];int[] id = new int[255555];Que Q = new Que();int new_node() {int i;for (i = 0; i < 26; i++)c[i][tot] = 0;fail[tot] = id[tot] = 0;return tot++;}void init() {tot = 0;Q.init();new_node();}char[] s1 = new char[111111];void insert(String s) {s1 = s.toCharArray();int now = 0;int l = s1.length, i;for (i = 0; i < l; i++) {int k = s1[i] - 'a';if (c[k][now] == 0)c[k][now] = new_node();now = c[k][now];}id[now]++;}void get_fail() {int u = 0, e, i;for (i = 0; i < 26; i++)if (c[i][u] != 0)Q.push(c[i][u]);while (Q.empty() == 0) {u = Q.front();Q.pop();for (i = 0; i < 26; i++) {if (c[i][u] != 0) {e = c[i][u];fail[e] = c[i][fail[u]];Q.push(e);} elsec[i][u] = c[i][fail[u]];}}}int work(String s) {s1 = s.toCharArray();int l = s1.length;int i, u = 0, j, sum = 0;;for (i = 0; i < l; i++) {int k = s1[i] - 'a';u = c[k][u];j = u;while (j != 0) {if (id[j] != 0) {sum += id[j];id[j] = 0;}j = fail[j];}}return sum;}}public class Main {static InputStream inputstream = System.in;    static PrintStream outputstream = System.out;    static InputReader in = new InputReader(inputstream);    static PrintWriter out = new PrintWriter(outputstream);    public static void main(String args[]) throws Exception {  Main task = new Main(); task.main(); out.close () ;}String s;static AC_auto ac = new AC_auto();void main() throws Exception {int cas, n;cas = in.nextInt();for (; cas > 0; cas--) {ac.init();n = in.nextInt();for (; n > 0; n--) {s = in.next();ac.insert(s);}ac.get_fail();s = in.next();out.println(ac.work(s));}}}class InputReader {BufferedReader reader;StringTokenizer tokenizer;InputReader(InputStream stream) {reader = new BufferedReader(new InputStreamReader(stream));tokenizer = null;}String next() {if (!hasNext())throw new RuntimeException();return tokenizer.nextToken();}boolean hasNext() {while (tokenizer == null || !tokenizer.hasMoreTokens())try {tokenizer = new StringTokenizer(reader.readLine());} catch (Exception e) {return false;}return true;}long nextLong() {return Long.parseLong(next());}int nextInt() {return Integer.parseInt(next());}}