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:heavy_check_mark: string/string-search.hpp

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#pragma once

#include "../atcoder/string.hpp"
#include "../data-structure/sparse-table.hpp"

template <typename Container>
struct StringSearch {
  const Container& S;
  int N;
  vector<int> sa, la, invsa;
  SparseTable<int> sparse;

  StringSearch(const Container& _s) : S(_s), N(S.size()) {
    sa = atcoder::suffix_array(S);
    la = atcoder::lcp_array(S, sa);
    invsa.resize(N);
    for (int i = 0; i < N; i++) invsa[sa[i]] = i;
    sparse = SparseTable<int>{la};
  }

  // lcp(s[i, N), s[j, N))
  int lcp(int i, int j) {
    assert(0 <= min(i, j) and max(i, j) < N);
    if (i == j) return N - i;
    int x = min(invsa[i], invsa[j]);
    int y = max(invsa[i], invsa[j]);
    return sparse.query(x, y);
  }
  // lcp(s[a, b), s[c, d))
  int lcp(int a, int b, int c, int d) {
    assert(0 <= a and a <= b and b <= N);
    assert(0 <= c and c <= d and d <= N);
    int l = lcp(a, c);
    return min({l, b - a, d - c});
  }
  // lcp(s[a, b), s[c, d))
  template <typename Int>
  int lcp(pair<Int, Int> p, pair<Int, Int> q) {
    return lcp(p.first, p.second, q.first, q.second);
  }

  // s[i, N) > s[j, N) : 1
  // s[i, N) = s[j, N) : 0
  // s[i, N) < s[j, N) : -1
  int strcmp(int i, int j) {
    assert(0 <= min(i, j) and max(i, j) < N);
    if (i == j) return 0;
    return invsa[i] < invsa[j] ? -1 : 1;
  }

  // s[a, b) > s[c, d) : 1
  // s[a, b) = s[c, d) : 0
  // s[a, b) < s[c, d) : -1
  int strcmp(int a, int b, int c, int d) {
    int l = lcp(a, b, c, d);
    return a + l == b            ? (c + l == d ? 0 : -1)
           : c + l == d          ? 1
           : S[a + l] < S[c + l] ? -1
                                 : 1;
  }
  // s[a, b) > s[c, d) : 1
  // s[a, b) = s[c, d) : 0
  // s[a, b) < s[c, d) : -1
  template <typename Int>
  int strcmp(pair<Int, Int> p, pair<Int, Int> q) {
    return strcmp(p.first, p.second, q.first, q.second);
  }
};
#line 2 "string/string-search.hpp"

#line 1 "atcoder/string.hpp"



#include <algorithm>
#include <cassert>
#include <numeric>
#include <string>
#include <vector>

namespace atcoder {

namespace internal {

std::vector<int> sa_naive(const std::vector<int>& s) {
    int n = int(s.size());
    std::vector<int> sa(n);
    std::iota(sa.begin(), sa.end(), 0);
    std::sort(sa.begin(), sa.end(), [&](int l, int r) {
        if (l == r) return false;
        while (l < n && r < n) {
            if (s[l] != s[r]) return s[l] < s[r];
            l++;
            r++;
        }
        return l == n;
    });
    return sa;
}

std::vector<int> sa_doubling(const std::vector<int>& s) {
    int n = int(s.size());
    std::vector<int> sa(n), rnk = s, tmp(n);
    std::iota(sa.begin(), sa.end(), 0);
    for (int k = 1; k < n; k *= 2) {
        auto cmp = [&](int x, int y) {
            if (rnk[x] != rnk[y]) return rnk[x] < rnk[y];
            int rx = x + k < n ? rnk[x + k] : -1;
            int ry = y + k < n ? rnk[y + k] : -1;
            return rx < ry;
        };
        std::sort(sa.begin(), sa.end(), cmp);
        tmp[sa[0]] = 0;
        for (int i = 1; i < n; i++) {
            tmp[sa[i]] = tmp[sa[i - 1]] + (cmp(sa[i - 1], sa[i]) ? 1 : 0);
        }
        std::swap(tmp, rnk);
    }
    return sa;
}

// SA-IS, linear-time suffix array construction
// Reference:
// G. Nong, S. Zhang, and W. H. Chan,
// Two Efficient Algorithms for Linear Time Suffix Array Construction
template <int THRESHOLD_NAIVE = 10, int THRESHOLD_DOUBLING = 40>
std::vector<int> sa_is(const std::vector<int>& s, int upper) {
    int n = int(s.size());
    if (n == 0) return {};
    if (n == 1) return {0};
    if (n == 2) {
        if (s[0] < s[1]) {
            return {0, 1};
        } else {
            return {1, 0};
        }
    }
    if (n < THRESHOLD_NAIVE) {
        return sa_naive(s);
    }
    if (n < THRESHOLD_DOUBLING) {
        return sa_doubling(s);
    }

    std::vector<int> sa(n);
    std::vector<bool> ls(n);
    for (int i = n - 2; i >= 0; i--) {
        ls[i] = (s[i] == s[i + 1]) ? ls[i + 1] : (s[i] < s[i + 1]);
    }
    std::vector<int> sum_l(upper + 1), sum_s(upper + 1);
    for (int i = 0; i < n; i++) {
        if (!ls[i]) {
            sum_s[s[i]]++;
        } else {
            sum_l[s[i] + 1]++;
        }
    }
    for (int i = 0; i <= upper; i++) {
        sum_s[i] += sum_l[i];
        if (i < upper) sum_l[i + 1] += sum_s[i];
    }

    auto induce = [&](const std::vector<int>& lms) {
        std::fill(sa.begin(), sa.end(), -1);
        std::vector<int> buf(upper + 1);
        std::copy(sum_s.begin(), sum_s.end(), buf.begin());
        for (auto d : lms) {
            if (d == n) continue;
            sa[buf[s[d]]++] = d;
        }
        std::copy(sum_l.begin(), sum_l.end(), buf.begin());
        sa[buf[s[n - 1]]++] = n - 1;
        for (int i = 0; i < n; i++) {
            int v = sa[i];
            if (v >= 1 && !ls[v - 1]) {
                sa[buf[s[v - 1]]++] = v - 1;
            }
        }
        std::copy(sum_l.begin(), sum_l.end(), buf.begin());
        for (int i = n - 1; i >= 0; i--) {
            int v = sa[i];
            if (v >= 1 && ls[v - 1]) {
                sa[--buf[s[v - 1] + 1]] = v - 1;
            }
        }
    };

    std::vector<int> lms_map(n + 1, -1);
    int m = 0;
    for (int i = 1; i < n; i++) {
        if (!ls[i - 1] && ls[i]) {
            lms_map[i] = m++;
        }
    }
    std::vector<int> lms;
    lms.reserve(m);
    for (int i = 1; i < n; i++) {
        if (!ls[i - 1] && ls[i]) {
            lms.push_back(i);
        }
    }

    induce(lms);

    if (m) {
        std::vector<int> sorted_lms;
        sorted_lms.reserve(m);
        for (int v : sa) {
            if (lms_map[v] != -1) sorted_lms.push_back(v);
        }
        std::vector<int> rec_s(m);
        int rec_upper = 0;
        rec_s[lms_map[sorted_lms[0]]] = 0;
        for (int i = 1; i < m; i++) {
            int l = sorted_lms[i - 1], r = sorted_lms[i];
            int end_l = (lms_map[l] + 1 < m) ? lms[lms_map[l] + 1] : n;
            int end_r = (lms_map[r] + 1 < m) ? lms[lms_map[r] + 1] : n;
            bool same = true;
            if (end_l - l != end_r - r) {
                same = false;
            } else {
                while (l < end_l) {
                    if (s[l] != s[r]) {
                        break;
                    }
                    l++;
                    r++;
                }
                if (l == n || s[l] != s[r]) same = false;
            }
            if (!same) rec_upper++;
            rec_s[lms_map[sorted_lms[i]]] = rec_upper;
        }

        auto rec_sa =
            sa_is<THRESHOLD_NAIVE, THRESHOLD_DOUBLING>(rec_s, rec_upper);

        for (int i = 0; i < m; i++) {
            sorted_lms[i] = lms[rec_sa[i]];
        }
        induce(sorted_lms);
    }
    return sa;
}

}  // namespace internal

std::vector<int> suffix_array(const std::vector<int>& s, int upper) {
    assert(0 <= upper);
    for (int d : s) {
        assert(0 <= d && d <= upper);
    }
    auto sa = internal::sa_is(s, upper);
    return sa;
}

template <class T> std::vector<int> suffix_array(const std::vector<T>& s) {
    int n = int(s.size());
    std::vector<int> idx(n);
    iota(idx.begin(), idx.end(), 0);
    sort(idx.begin(), idx.end(), [&](int l, int r) { return s[l] < s[r]; });
    std::vector<int> s2(n);
    int now = 0;
    for (int i = 0; i < n; i++) {
        if (i && s[idx[i - 1]] != s[idx[i]]) now++;
        s2[idx[i]] = now;
    }
    return internal::sa_is(s2, now);
}

std::vector<int> suffix_array(const std::string& s) {
    int n = int(s.size());
    std::vector<int> s2(n);
    for (int i = 0; i < n; i++) {
        s2[i] = s[i];
    }
    return internal::sa_is(s2, 255);
}

// Reference:
// T. Kasai, G. Lee, H. Arimura, S. Arikawa, and K. Park,
// Linear-Time Longest-Common-Prefix Computation in Suffix Arrays and Its
// Applications
template <class T>
std::vector<int> lcp_array(const std::vector<T>& s,
                           const std::vector<int>& sa) {
    int n = int(s.size());
    assert(n >= 1);
    std::vector<int> rnk(n);
    for (int i = 0; i < n; i++) {
        rnk[sa[i]] = i;
    }
    std::vector<int> lcp(n - 1);
    int h = 0;
    for (int i = 0; i < n; i++) {
        if (h > 0) h--;
        if (rnk[i] == 0) continue;
        int j = sa[rnk[i] - 1];
        for (; j + h < n && i + h < n; h++) {
            if (s[j + h] != s[i + h]) break;
        }
        lcp[rnk[i] - 1] = h;
    }
    return lcp;
}

std::vector<int> lcp_array(const std::string& s, const std::vector<int>& sa) {
    int n = int(s.size());
    std::vector<int> s2(n);
    for (int i = 0; i < n; i++) {
        s2[i] = s[i];
    }
    return lcp_array(s2, sa);
}

// Reference:
// D. Gusfield,
// Algorithms on Strings, Trees, and Sequences: Computer Science and
// Computational Biology
template <class T> std::vector<int> z_algorithm(const std::vector<T>& s) {
    int n = int(s.size());
    if (n == 0) return {};
    std::vector<int> z(n);
    z[0] = 0;
    for (int i = 1, j = 0; i < n; i++) {
        int& k = z[i];
        k = (j + z[j] <= i) ? 0 : std::min(j + z[j] - i, z[i - j]);
        while (i + k < n && s[k] == s[i + k]) k++;
        if (j + z[j] < i + z[i]) j = i;
    }
    z[0] = n;
    return z;
}

std::vector<int> z_algorithm(const std::string& s) {
    int n = int(s.size());
    std::vector<int> s2(n);
    for (int i = 0; i < n; i++) {
        s2[i] = s[i];
    }
    return z_algorithm(s2);
}

}  // namespace atcoder


#line 2 "data-structure/sparse-table.hpp"

#line 4 "data-structure/sparse-table.hpp"
#include <limits>
#line 6 "data-structure/sparse-table.hpp"
using namespace std;

template <typename T>
struct SparseTable {
  inline static constexpr T INF = numeric_limits<T>::max() / 2;
  int N;
  vector<vector<T> > table;
  T f(T a, T b) { return min(a, b); }
  SparseTable() {}
  SparseTable(const vector<T> &v) : N(v.size()) {
    int b = 1;
    while ((1 << b) <= N) ++b;
    table.push_back(v);
    for (int i = 1; i < b; i++) {
      table.push_back(vector<T>(N, INF));
      for (int j = 0; j + (1 << i) <= N; j++) {
        table[i][j] = f(table[i - 1][j], table[i - 1][j + (1 << (i - 1))]);
      }
    }
  }
  // [l, r)
  T query(int l, int r) {
    assert(0 <= l and l <= r and r <= N);
    if (l == r) return INF;
    int b = 31 - __builtin_clz(r - l);
    return f(table[b][l], table[b][r - (1 << b)]);
  }
};

/**
 * @brief Sparse Table
 */
#line 5 "string/string-search.hpp"

template <typename Container>
struct StringSearch {
  const Container& S;
  int N;
  vector<int> sa, la, invsa;
  SparseTable<int> sparse;

  StringSearch(const Container& _s) : S(_s), N(S.size()) {
    sa = atcoder::suffix_array(S);
    la = atcoder::lcp_array(S, sa);
    invsa.resize(N);
    for (int i = 0; i < N; i++) invsa[sa[i]] = i;
    sparse = SparseTable<int>{la};
  }

  // lcp(s[i, N), s[j, N))
  int lcp(int i, int j) {
    assert(0 <= min(i, j) and max(i, j) < N);
    if (i == j) return N - i;
    int x = min(invsa[i], invsa[j]);
    int y = max(invsa[i], invsa[j]);
    return sparse.query(x, y);
  }
  // lcp(s[a, b), s[c, d))
  int lcp(int a, int b, int c, int d) {
    assert(0 <= a and a <= b and b <= N);
    assert(0 <= c and c <= d and d <= N);
    int l = lcp(a, c);
    return min({l, b - a, d - c});
  }
  // lcp(s[a, b), s[c, d))
  template <typename Int>
  int lcp(pair<Int, Int> p, pair<Int, Int> q) {
    return lcp(p.first, p.second, q.first, q.second);
  }

  // s[i, N) > s[j, N) : 1
  // s[i, N) = s[j, N) : 0
  // s[i, N) < s[j, N) : -1
  int strcmp(int i, int j) {
    assert(0 <= min(i, j) and max(i, j) < N);
    if (i == j) return 0;
    return invsa[i] < invsa[j] ? -1 : 1;
  }

  // s[a, b) > s[c, d) : 1
  // s[a, b) = s[c, d) : 0
  // s[a, b) < s[c, d) : -1
  int strcmp(int a, int b, int c, int d) {
    int l = lcp(a, b, c, d);
    return a + l == b            ? (c + l == d ? 0 : -1)
           : c + l == d          ? 1
           : S[a + l] < S[c + l] ? -1
                                 : 1;
  }
  // s[a, b) > s[c, d) : 1
  // s[a, b) = s[c, d) : 0
  // s[a, b) < s[c, d) : -1
  template <typename Int>
  int strcmp(pair<Int, Int> p, pair<Int, Int> q) {
    return strcmp(p.first, p.second, q.first, q.second);
  }
};
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