// find the suffix array SA of s[0..n-1] in {1..K}^n // require s[n]=s[n+1]=s[n+2]=0, n>=2 static void suffixArray(int[] s, int[] SA, int n, int K) { int n0 = (n + 2) / 3, n1 = (n + 1) / 3, n2 = n / 3, n02 = n0 + n2; int[] s12 = new int[n02 + 3]; s12[n02] = s12[n02 + 1] = s12[n02 + 2] = 0; int[] SA12 = new int[n02 + 3]; SA12[n02] = SA12[n02 + 1] = SA12[n02 + 2] = 0; int[] s0 = new int[n0]; int[] SA0 = new int[n0]; for (int i = 0, j = 0; i < n + (n0 - n1); i++) if (i % 3 != 0) s12[j++] = i; radixPass(s12, SA12, s, n02, K, 2); radixPass(SA12, s12, s, n02, K, 1); radixPass(s12, SA12, s, n02, K, 0); int name = 0, c0 = -1, c1 = -1, c2 = -1; for (int i = 0; i < n02; i++) { if (s[SA12[i]] != c0 || s[SA12[i] + 1] != c1 || s[SA12[i] + 2] != c2) { name++; c0 = s[SA12[i]]; c1 = s[SA12[i] + 1]; c2 = s[SA12[i] + 2]; } if (SA12[i] % 3 == 1) s12[SA12[i] / 3] = name; else s12[SA12[i] / 3 + n0] = name; } if (name < n02) { suffixArray(s12, SA12, n02, name); for (int i = 0; i < n02; i++) s12[SA12[i]] = i + 1; } else for (int i = 0; i < n02; i++) SA12[s12[i] - 1] = i; for (int i = 0, j = 0; i < n02; i++) if (SA12[i] < n0) s0[j++] = 3 * SA12[i]; radixPass(s0, SA0, s, n0, K, 0); for (int p = 0, t = n0 - n1, k = 0; k < n; k++) { int i = (SA12[t] < n0 ? SA12[t] * 3 + 1 : (SA12[t] - n0) * 3 + 2); int j = SA0[p]; if (SA12[t] < n0 ? leq(s[i], s12[SA12[t] + n0], s[j], s12[j / 3]) : leq(s[i], s[i + 1], s12[SA12[t] - n0 + 1], s[j], s[j + 1], s12[j / 3 + n0])) { SA[k] = i; t++; if (t == n02) for (k++; p < n0; p++, k++) SA[k] = SA0[p]; } else { SA[k] = j; p++; if (p == n0) for (k++; t < n02; t++, k++) SA[k] = (SA12[t] < n0 ? SA12[t] * 3 + 1 : (SA12[t] - n0) * 3 + 2); } } }