Problem p01756 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>

using namespace std;

#define MAX 310000

struct Suffix_Array {
  int N, k;
  vector<int> sa;

  Suffix_Array(const string &S) : N(S.size()), sa(N + 1) {
    vector<int> rnk(N + 1), tmp(N + 1);
    for (int i = 0; i <= N; i++) {
      sa[i] = i;
      rnk[i] = (i < N ? S[i] : -1);
    }

    for (k = 1; k <= N; k *= 2) {
      const auto comp = [&](int i, int j) -> bool {
        if (rnk[i] != rnk[j]) {
          return rnk[i] < rnk[j];
        } else {
          int ri = (i + k <= N ? rnk[i + k] : -1);
          int rj = (j + k <= N ? rnk[j + k] : -1);
          return ri < rj;
        }
      };

      sort(sa.begin(), sa.end(), comp);

      tmp[sa[0]] = 0;
      for (int i = 1; i <= N; i++) {
        tmp[sa[i]] = tmp[sa[i - 1]] + (comp(sa[i - 1], sa[i]));
      }

      for (int i = 0; i <= N; i++) {
        rnk[i] = tmp[i];
      }
    }
  }

  int lower_bound(const string &S, const string &T) {
    int l = 0, r = N;
    while (r - l > 1) {
      int mid = (l + r) / 2;
      if (S.compare(sa[mid], T.size(), T) < 0) {
        l = mid;
      } else {
        r = mid;
      }
    }
    return (S.compare(sa[r], T.size(), T) == 0 ? r : -1);
  }

  int upper_bound(const string &S, const string &T) {
    int l = 1, r = N + 1;
    while (r - l > 1) {
      int mid = (l + r) / 2;
      if (S.compare(sa[mid], T.size(), T) <= 0) {
        l = mid;
      } else {
        r = mid;
      }
    }
    return (S.compare(sa[l], T.size(), T) == 0 ? r : -1);
  }
};

struct RMQ {
  int n, dat[2 * MAX - 1];

  void init(int n_) {
    n = 1;
    while (n < n_) {
      n *= 2;
    }
    for (int i = 0; i < 2 * n - 1; i++) {
      dat[i] = INT_MAX;
    }
  }

  void update(int k, int a) {
    k += n - 1;
    dat[k] = a;
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = min(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }

  int query(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) {
      return INT_MAX;
    }
    if (a <= l && r <= b) {
      return dat[k];
    } else {
      int vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
      int vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return min(vl, vr);
    }
  }
};

struct RMQ2 {
  int n, dat[2 * MAX - 1];

  void init(int n_) {
    n = 1;
    while (n < n_) {
      n *= 2;
    }
    for (int i = 0; i < 2 * n - 1; i++) {
      dat[i] = INT_MIN;
    }
  }

  void update(int k, int a) {
    k += n - 1;
    dat[k] = a;
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = max(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }

  int query(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) {
      return INT_MIN;
    }
    if (a <= l && r <= b) {
      return dat[k];
    } else {
      int vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
      int vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return max(vl, vr);
    }
  }
};

int main() {
  ios::sync_with_stdio(0);

  int Q, N;
  string S, R, x, y;

  cin >> S >> Q;

  Suffix_Array SA(S);

  N = S.size() + 1;
  RMQ rmq1;
  RMQ2 rmq2;
  rmq1.init(N);
  rmq2.init(N);
  for (int i = 0; i < N; i++) {
    rmq1.update(i, SA.sa[i]);
    rmq2.update(i, SA.sa[i]);
  }

  while (Q--) {
    cin >> x >> y;
    int lb_x = SA.lower_bound(S, x), ub_x = SA.upper_bound(S, x);
    int lb_y = SA.lower_bound(S, y), ub_y = SA.upper_bound(S, y);
    if (lb_x == -1 || ub_x == -1 || lb_y == -1 || ub_y == -1) {
      cout << 0 << endl;
      continue;
    }

    int l = rmq1.query(lb_x, ub_x, 0, 0, rmq1.n);
    int r = rmq2.query(lb_y, ub_y, 0, 0, rmq2.n);

    if (l > r || (l <= r && r + (int)y.size() < l + (int)x.size())) {
      cout << 0 << endl;
      continue;
    }

    cout << r - l + (int)y.size() << endl;
  }
  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>

using namespace std;

#define MAX 210000

struct SA_Comp {
  int k;
  vector<int> rnk;

  SA_Comp(int k, vector<int> &rnk) : k(k), rnk(rnk) {}

  bool operator()(int i, int j) const {
    int N = rnk.size();
    if (rnk[i] != rnk[j]) {
      return rnk[i] < rnk[j];
    } else {
      int ri = (i + k <= N ? rnk[i + k] : -1);
      int rj = (j + k <= N ? rnk[j + k] : -1);
      return ri < rj;
    }
  }
};

struct Suffix_Array {
  int N, k;
  vector<int> sa;

  Suffix_Array(const string &S) : N(S.size()), sa(N + 1) {
    vector<int> rnk(N + 1), tmp(N + 1);
    for (int i = 0; i <= N; i++) {
      sa[i] = i;
      rnk[i] = (i < N ? S[i] : -1);
    }

    for (k = 1; k <= N; k *= 2) {
      SA_Comp comp(k, rnk);
      sort(sa.begin(), sa.end(), comp);

      tmp[sa[0]] = 0;
      for (int i = 1; i <= N; i++) {
        tmp[sa[i]] = tmp[sa[i - 1]] + (comp(sa[i - 1], sa[i]));
      }

      for (int i = 0; i <= N; i++) {
        rnk[i] = tmp[i];
      }
    }
  }

  int lower_bound(const string &S, const string &T) {
    int l = 0, r = N;
    while (r - l > 1) {
      int mid = (l + r) / 2;
      if (S.compare(sa[mid], T.size(), T) < 0) {
        l = mid;
      } else {
        r = mid;
      }
    }
    return (S.compare(sa[r], T.size(), T) == 0 ? r : -1);
  }

  int upper_bound(const string &S, const string &T) {
    int l = 1, r = N + 1;
    while (r - l > 1) {
      int mid = (l + r) / 2;
      if (S.compare(sa[mid], T.size(), T) <= 0) {
        l = mid;
      } else {
        r = mid;
      }
    }
    return (S.compare(sa[l], T.size(), T) == 0 ? r : -1);
  }
};

struct RMQ {
  int n, dat[2 * MAX - 1];

  void init(int n_) {
    n = 1;
    while (n < n_) {
      n *= 2;
    }
    for (int i = 0; i < 2 * n - 1; i++) {
      dat[i] = INT_MAX;
    }
  }

  void update(int k, int a) {
    k += n - 1;
    dat[k] = a;
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = min(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }

  int query(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) {
      return INT_MAX;
    }
    if (a <= l && r <= b) {
      return dat[k];
    } else {
      int vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
      int vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return min(vl, vr);
    }
  }
};

struct RMQ2 {
  int n, dat[2 * MAX - 1];

  void init(int n_) {
    n = 1;
    while (n < n_) {
      n *= 2;
    }
    for (int i = 0; i < 2 * n - 1; i++) {
      dat[i] = INT_MIN;
    }
  }

  void update(int k, int a) {
    k += n - 1;
    dat[k] = a;
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = max(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }

  int query(int a, int b, int k, int l, int r) {
    if (r <= a || b <= l) {
      return INT_MIN;
    }
    if (a <= l && r <= b) {
      return dat[k];
    } else {
      int vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
      int vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return max(vl, vr);
    }
  }
};

int main() {
  ios::sync_with_stdio(0);

  int Q, N;
  string S, R, x, y;

  cin >> S >> Q;

  Suffix_Array SA(S);

  N = S.size() + 1;
  RMQ rmq;
  RMQ2 rmq2;
  rmq.init(N);
  rmq2.init(N);
  for (int i = 0; i < N; i++) {
    rmq.update(i, SA.sa[i]);
    rmq2.update(i, SA.sa[i]);
  }

  while (Q--) {
    cin >> x >> y;
    int lb_x = SA.lower_bound(S, x), ub_x = SA.upper_bound(S, x);
    int lb_y = SA.lower_bound(S, y), ub_y = SA.upper_bound(S, y);
    if (lb_x == -1 || ub_x == -1 || lb_y == -1 || ub_y == -1) {
      cout << 0 << endl;
      continue;
    }

    // cout << lb_x << " " << ub_x << " " << lb_y << " " << ub_y <<
    int l = rmq.query(lb_x, ub_x, 0, 0, rmq.n);
    int r = rmq2.query(lb_y, ub_y, 0, 0, rmq2.n);

    if (l > r || (l <= r && r + (int)y.size() < l + (int)x.size())) {
      cout << 0 << endl;
      continue;
    }

    cout << r - l + (int)y.size() << endl;
  }
  return 0;
}