loj 3311「ZJOI2020」字符串 - 平方串

#include <bits/stdc++.h>
using namespace std;
typedef bool boolean;

template <typename T>
void pfill(T* pst, const T* ped, T val) {
  for ( ; pst != ped; *(pst++) = val);
}

const int N = 2e5 + 5;
const int bzmax = 19;

typedef class SparseTable {
  public:
    int n;
    int *a;
    int log2[N];
    int f[bzmax][N];

    SparseTable() {	}

    void init(int n, int *a) {
      this->n = n, this->a = a;
      log2[0] = -1;
      for (int i = 1; i <= n; i++) {
        log2[i] = log2[i >> 1] + 1;
      }
      for (int i = 1; i <= n; i++) {
        f[0][i] = a[i];
      }
      for (int i = 1; i < bzmax; i++) {
        for (int j = 1; j + (1 << i) - 1 <= n; j++) {
          f[i][j] = min(f[i - 1][j], f[i - 1][j + (1 << (i - 1))]);
        }
      }
    }

    int query(int l, int r) {
      int b = log2[r - l + 1];
      return min(f[b][l], f[b][r - (1 << b) + 1]);
    }
} SparseTable;

typedef class Pair3 {
  public:
    int x, y, id;

    Pair3() {	}
    Pair3(int x, int y, int id) : x(x), y(y), id(id) {	}
} Pair3;

typedef class SuffixArray {
  public:
    int n;
    char *str;
    int cnt[N];
    SparseTable st;
    Pair3 X[N], Y[N];
    int sa[N], rk[N], hei[N];

    SuffixArray() {	}

    void set(int n, char* str) {
      this->n = n, this->str = str;
    }

    void radix_sort() {
      int m = max(256, n);
      pfill(cnt, cnt + m + 1, 0);
      for (int i = 1; i <= n; i++)
        cnt[X[i].y]++;
      for (int i = 1; i <= m; i++)
        cnt[i] += cnt[i - 1];
      for (int i = 1; i <= n; i++)
        Y[cnt[X[i].y]--] = X[i];

      pfill(cnt, cnt + m + 1, 0);
      for (int i = 1; i <= n; i++)
        cnt[Y[i].x]++;
      for (int i = 1; i <= m; i++)
        cnt[i] += cnt[i - 1];
      for (int i = n; i; i--)
        X[cnt[Y[i].x]--] = Y[i];
    }

    void build() {
      for (int i = 1; i <= n; i++)
        rk[i] = str[i];
      for (int k = 1; k <= n; k <<= 1) {
        for (int i = 1; i + k <= n; i++)
          X[i] = Pair3(rk[i], rk[i + k], i);
        for (int i = n - k + 1; i <= n; i++)
          X[i] = Pair3(rk[i], 0, i);
        radix_sort();
        int dif = 1;
        rk[X[1].id] = 1;
        for (int i = 2; i <= n; i++)
          rk[X[i].id] = (X[i].x == X[i - 1].x && X[i].y == X[i - 1].y) ? (dif) : (++dif);
        if (dif == n) {
          break;
        }
      }
      for (int i = 1; i <= n; i++) {
        sa[rk[i]] = i;
      }
    }

    void get_height() {
      for (int i = 1, j, k = 0; i <= n; i++, k && k--) {
        if (rk[i]) {
          for (j = sa[rk[i] - 1]; i + k <= n && j + k <= n && str[i + k] == str[j + k]; k++);
          hei[rk[i]] = k;
        }
      }
    }

    void init_st() {
      st.init(n, hei);
    }

    int lcp(int u, int v) {
      if (u == v) {
        return n - u + 1;
      }
      u = rk[u], v = rk[v];
      if (u > v) swap(u, v);
      return st.query(u + 1, v);
    }

    int compare(int l1, int r1, int l2, int r2) {
      int len_lcp = lcp(l1, l2);
      int R1 = l1 + len_lcp, R2 = l2 + len_lcp;
      if (R1 > r1 && R2 > r2)
        return ((r1 - l1) > (r2 - l2)) ? (1) : ((r1 - l1 == r2 - l2) ? (0) : (-1));
      if (R1 > r1 || R2 > r2)
        return (R1 > r1) ? (-1) : (1);
      return (str[R1] < str[R2]) ? (-1) : (1);
    }

    int operator [] (int p) {
      return sa[p];
    }
    int operator () (int p) {
      return hei[p];
    }

    void work(int n, char* s) {
      set(n, s);
      build();
      get_height();
      init_st();
    }
} SuffixArray;

typedef class Fenwick {
  public:
    int n;
    vector<int> a;

    void init(int n) {
      this->n = n;
      a.assign(n + 1, 0);
    }
    void add(int idx, int val) {
      for ( ; idx <= n; idx += idx & (-idx))
        a[idx] += val;
    }
    int qry(int idx) {
      int ret = 0;
      for ( ; idx; idx -= (idx & (-idx)))
        ret += a[idx];
      return ret;
    }
} Fenwick;

typedef class Runs {
  public:
    int l, r, d;
    vector<pair<int, int>> range;

    Runs() {  }
    Runs(int l, int r, int d) : l(l), r(r), d(d) { }

    int query(int ql, int qr) {
      ql = max(ql, l);
      qr = min(qr, r + d);
      int ret = 0;
      for (auto rg : range) {
        int rl = rg.first, rr = rg.second;
        if (ql > rl && qr < rr) {
          int cl = rl + (ql - rl + d - 1) / d * d;
          ret += (qr + 1 - cl) / (d << 1);
        }
      }
      return ret;
    }
} Runs;

int n, q;
int ans[N];
vector<Runs> vr;
char s[N], _s[N];
SuffixArray sa, _sa;

typedef class Segment {
  public:
    int l, r;

    Segment() { }
    Segment(int l, int r) : l(l), r(r) {  }

    bool operator < (Segment b) const {
      return sa.compare(l, r, b.l, b.r) == -1;
    }
} Segment;

typedef class Event {
  public:
    int op, x, y, v;

    Event(int op, int x, int y, int v) : op(op), x(x), y(y), v(v) {
      //      cerr << "Event created: " << op << " " << x << " " << y << " " << v << ‘\n‘;
    } 

    bool operator < (Event b) const {
      return (x ^ b.x) ? (x > b.x) : (op < b.op);
    }
} Event;

int Less[N];
bool ban[N * 20];
vector<int> cov[N];
map<Segment, int> mpls;
vector<Event> E;

void init_runs() {
  for (int i = 1; i <= n; i++) {
    Less[i + 1] = Less[i] + (n / i);
  }
  for (int d = 1; (d << 1) <= n; d++) {
    int l, r = 0;
    mpls.clear();
    for (int i = d; i + d <= n; i += d) {
      if (i > r) {
        int _i = i + d;
        l = i - _sa.lcp(n - _i + 1, n - i + 1) + 1;
        r = i + sa.lcp(i, _i) - 1;
        if (r - l + 1 < d || ban[Less[d] + i / d]) {
          continue;
        }
        for (int p = d << 1; l + (p << 1) - 1 <= r + d; p = p + d) {
          ban[Less[p] + (l + p - 1) / p] = true;
        }
        for (int j = l; j <= r; j++) {
          cov[j].push_back(vr.size());
        }
        //        cerr << "runs found: " << l << " " << r << " with period " << d << ‘\n‘;
        vr.emplace_back(l, r, d);
        int d2 = d << 1;
        for (int j = 0; j < d && l + j + d - 1 <= r; j++) {
          int R = l + j + (r + d - l - j + 1) / d * d;
          vr.back().range.emplace_back(l + j, R - 1);
          for (int t = d2; l + j + t - 1 <= r + d; t += d2) {
            int pl = l + j, pr = R - t;
            E.emplace_back(0, pl, pl + t - 1, 1);
            E.emplace_back(0, pr, pr + t - 1, 1);
            E.emplace_back(0, pl, pr + t - 1, -1);
            Segment s = Segment(pl, pl + t - 1);
            if (mpls.count(s)) {
              int pls = mpls[s];
              E.emplace_back(0, pls, pl + t - 1, -1);
            }
            mpls[s] = pr;
          }
        }
      }
    }
  }
}

int main() {
  scanf("%d%d", &n, &q);
  scanf("%s", s + 1);
  for (int i = 1; i <= n; i++) {
    _s[n - i + 1] = s[i];
  }
  sa.work(n, s);
  _sa.work(n, _s);
  init_runs();
  for (int i = 1, l, r; i <= q; i++) {
    scanf("%d%d", &l, &r);
    E.emplace_back(1, l, r, i);
    for (auto x : cov[l]) {
      ans[i] += vr[x].query(l, r);
    }
  }
  Fenwick fen;
  fen.init(n);
  sort(E.begin(), E.end());
  for (auto e : E) {
    if (!e.op) {
      fen.add(e.y, e.v);
    } else {
      ans[e.v] += fen.qry(e.y);
    }
  }
  for (int i = 1; i <= q; i++) {
    printf("%d\n", ans[i]);
  }
  return 0;
}