AC自动机算法JAVA

import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class Didi {
private static Node root=new Node();
private static Queue<Node> queue=new LinkedList<Node>();
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
String[] word={"say","she","shr","he","her"};
String s="yasherhs";
for (int i = 0; i < word.length; i++) {
insert(word[i]);
}
build_ac_automation(root);
System.out.println(query(s));
}

public static int query(String s){
int count=0;
Node p=root;
char[] str=s.toCharArray();
for (int i = 0; i < str.length; i++) {
int index=str[i]-'a';
while(p.child[index]==null&&p!=root){
p=p.fail;
}
p=p.child[index];
p=(p==null)?root:p;
Node temp=p;
while(temp!=root&&temp.count!=-1){
count+=temp.count;
temp.count=-1;
temp=temp.fail;
}
}
return count;
}
public static void build_ac_automation(Node root){

root.fail=null;
queue.add(root);
while(!queue.isEmpty()){
Node temp=queue.poll();
Node p=null;
for (int i = 0; i < 26; i++) {
if(temp.child[i]!=null){
if(temp==root){
temp.child[i].fail=root;
}else{
p=temp.fail;
while(p!=null){
if(p.child[i]!=null){
temp.child[i].fail=p.child[i];
break;
}
p=p.fail;
}
if(p==null){
temp.child[i].fail=root;
}
}
queue.add(temp.child[i]);
}
}
}
}
public static void insert(String str){
if(str.isEmpty()||str==""){
return;
}
Node cnode=root;
for (int i = 0; i < str.length(); i++) {
int index=str.charAt(i)-'a';
if(cnode.child[index]==null){
Node pnode=new Node();
cnode.child[index]=pnode;
}
cnode=cnode.child[index];
}
cnode.count=1;
}
}

class Node{
int count;
Node fail;
Node[] child;
public Node(){
fail=null;
count=0;
child=new Node[26];
}
}