suffix_automaton.cpp

struct state
{
    int len, link;
    map<char, int> next;
};
const int N = 300000 + 5;

struct SA
{
    state st[2 * N];
    int fpos[2 * N];
    int sz, last;

    void sa_init()
    {
        sz = last = 0;
        st[0].len = 0;
        st[0].link = -1;
        ++sz;
    }

    void sa_extend(char c)
    {
        int cur = sz++;
        st[cur].len = st[last].len + 1;
        fpos[cur] = st[cur].len - 1;
        int p;
        for(p = last; p != -1 && !st[p].next.count(c); p = st[p].link)
            st[p].next[c] = cur;
        if(p == -1)
            st[cur].link = 0;
        else
        {
            int q = st[p].next[c];
            if(st[p].len + 1 == st[q].len)
                st[cur].link = q;
            else
            {
                int clone = sz++;
                st[clone].len = st[p].len + 1;
                st[clone].next = st[q].next;
                st[clone].link = st[q].link;
                fpos[clone] = fpos[q];
                for(; p != -1 && st[p].next[c] == q; p = st[p].link)
                    st[p].next[c] = clone;
                st[q].link = st[cur].link = clone;
            }
        }
        last = cur;
    }
};