后缀自动机

struct suffix_automaton
{
    string s;
    int son[maxn][26],pre[maxn],step[maxn],last,total;
    inline void push_back(int v)
    {
        step[++total]=v;
    }
    void Extend(char ch)
    {
        push_back(step[last]+1);
        int p=last,np=total;
        for (;!son[p][ch];p=pre[p]) son[p][ch]=np;
        if(!p) pre[np]=0;
        else
        {
            int q=son[p][ch];
            if(step[q]!=step[p]+1)
            {
                push_back(step[p]+1);
                int nq=total;
                memcpy(son[nq],son[q],sizeof(son[q]));
                pre[nq]=pre[q];
                pre[q]=pre[np]=nq;
                for (; son[p][ch]==q; p=pre[p]) son[p][ch]=nq;
            }  
            else pre[np]=q;
        }
        last=np;
    }
    void Build()
    {
        cin>>s;
        total=last=0;
        memset(son,0,sizeof(son));
        memset(pre,0,sizeof(pre));
        memset(step,0,sizeof(step));
        for (int i=0,End=s.size(); i!=End; i++) Extend(s[i]-'A');
        visit(0,0);
    }
}suf;