AC自动机模板

void getfail()   //建立fail指针
{
int i;
node *p;
p = root;
queue<struct node *>qu;
qu.push(p);
while (!qu.empty())
{
p = qu.front();
qu.pop();
for (i=0; i<26; i++)
{
if (p->child[i]!=NULL)
{
if (p==root)
{
p->child[i]->fail = root;
}
else
{
node * newnode= p->fail;
while (newnode!=NULL)
{
if (newnode->child[i]!=NULL)
{
p->child[i]->fail = newnode->child[i];
break;
}
newnode = newnode->fail;
}
if (newnode == NULL)
{
p->child[i]->fail = root;
}
}
qu.push(p->child[i]);
}
}
}
}