vector Z(const vector &s) { int n = sz(s); vector z(n, n); int l = 0, r = 0, p, q; for (int i = 1; i < n; ++i) { if (i <= r && z[i - l] < r - i + 1) { z[i] = z[i - l]; } else { if (i > r) p = 0, q = i; else p = r - i + 1, q = r + 1; while (q < n && s[p] == s[q]) ++p, ++q; z[i] = q - i, l = i, r = q - 1; }} return z; }