99 lines
2.8 KiB
C++
99 lines
2.8 KiB
C++
struct SA {
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int n;
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std::vector<int> sa, rk, lc;
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vector<vector<int>> st;
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SA(std::string s) {
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n = s.size();
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sa.resize(n);
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lc.resize(n - 1);
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rk.resize(n);
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std::iota(sa.begin(), sa.end(), 0);
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sort_by_key(sa.begin(), sa.end(), expr(s[i], int i));
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rk[sa[0]] = 0;
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for (int i = 1; i < n; i++) {
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rk[sa[i]] = rk[sa[i - 1]] + (s[sa[i]] != s[sa[i - 1]]);
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}
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int k = 1;
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std::vector<int> tmp, cnt(n);
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tmp.reserve(n);
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while (rk[sa[n - 1]] < n - 1) {
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tmp.clear();
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for (int i = 0; i < k; i++) {
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tmp.push_back(n - k + i);
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}
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for (auto i : sa) {
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if (i >= k) {
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tmp.push_back(i - k);
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}
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}
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std::fill(cnt.begin(), cnt.end(), 0);
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for (int i = 0; i < n; i++) {
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cnt[rk[i]]++;
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}
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for (int i = 1; i < n; i++) {
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cnt[i] += cnt[i - 1];
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}
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for (int i = n - 1; i >= 0; i--) {
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sa[--cnt[rk[tmp[i]]]] = tmp[i];
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}
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std::swap(rk, tmp);
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rk[sa[0]] = 0;
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for (int i = 1; i < n; i++) {
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rk[sa[i]] = rk[sa[i - 1]] + (tmp[sa[i - 1]] < tmp[sa[i]] || sa[i - 1] + k == n || tmp[sa[i - 1] + k] < tmp[sa[i] + k]);
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}
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k *= 2;
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}
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for (int i = 0, j = 0; i < n; i++) {
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if (rk[i] == 0) {
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j = 0;
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} else {
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for (j -= j > 0; i + j < n && sa[rk[i] - 1] + j < n && s[i + j] == s[sa[rk[i] - 1] + j]; ) {
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j++;
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}
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lc[rk[i] - 1] = j;
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}
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}
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int m = lc.size();
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int lgm = lg2(m);
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st = vector(lgm + 1, vector<int>(m));
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st[0] = lc;
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for (int j = 0; j < lgm; j++) {
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for (int i = 0; i + (2 << j) <= m; i++) {
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st[j + 1][i] = std::min(st[j][i], st[j][i + (1 << j)]);
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}
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}
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}
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int rmq(int l, int r) {
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int k = lg2(r - l);
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return std::min(st[k][l], st[k][r - (1 << k)]);
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}
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__attribute__((target("lzcnt")))
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int lcp(int i, int j) {
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if (i == j || i == n || j == n) {
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return std::min(n - i, n - j);
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}
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int a = rk[i];
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int b = rk[j];
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if (a > b) {
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std::swap(a, b);
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}
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deb(a, b, rmq(a, b));
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return std::min({n - i, n - j, rmq(a, b)});
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}
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int lcs(int i, int j) {
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if (i == j || i == 0 || j == 0) {
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return std::min(i, j);
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}
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int a = rk[n + n - i];
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int b = rk[n + n - j];
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if (a > b) {
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std::swap(a, b);
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}
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return std::min({i, j, rmq(a, b)});
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}
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};
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