后缀数组模板

struct SuffixAutomaton {
    static constexpr int N = 1e6;
    struct node {
        int len, link, nxt[26];
        int siz;
    } t[N << 1];
    int cntNodes;
    SuffixAutomaton() {
        cntNodes = 1;
        fill(t[0].nxt, t[0].nxt + 26, 1);
        t[0].len = -1;
    }
    int extend(int p, int c) {
        if (t[p].nxt[c]) {
            int q = t[p].nxt[c];
        if (t[q].len == t[p].len + 1) {
            return q;
        }
        int r = ++cntNodes;
        t[r].siz = 0;
        t[r].len = t[p].len + 1;
        t[r].link = t[q].link;
        copy(t[q].nxt, t[q].nxt + 26, t[r].nxt);
        t[q].link = r;
        while (t[p].nxt[c] == q) {
            t[p].nxt[c] = r;
            p = t[p].link;
        }
            return r;
        }
        int cur = ++cntNodes;
        t[cur].len = t[p].len + 1;
        t[cur].siz = 1;
        while (!t[p].nxt[c]) {
            t[p].nxt[c] = cur;
            p = t[p].link;
        }
        t[cur].link = extend(p, c);
            return cur;
        }

    int cal(string s){
        //计算字符串的本质不同子串数量
        int n=s.size();
        s=" "+s;
        int last=1;
        rep(i,1,n){
            last=extend(last,s[i]-'a');
        }
        int cnt=0;
        for(int i=2;i<=cntNodes;i++){
            cnt+=t[i].len-t[t[i].link].len;
        }
        return cnt;
    }
}SAM;