Problem p02575 (C++) — buggy submission, verdict: Time Limit Exceeded

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

#define int long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define reps(i, n) for (int i = 1; i <= (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define uniq(x) (x).erase(unique(all(x)), (x).end())
#define bit(n) (1LL << (n))
#define dump(x) cerr << #x " = " << (x) << endl
using vint = vector<int>;
using vvint = vector<vint>;
using pint = pair<int, int>;
using vpint = vector<pint>;
template <typename T>
using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
constexpr double PI = 3.1415926535897932384626433832795028;
constexpr int DY[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
constexpr int DX[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
int sign(int x) { return (x > 0) - (x < 0); }
int gcd(int a, int b) {
  while (b) {
    swap(a %= b, b);
  }
  return a;
}
int lcm(int a, int b) { return a / gcd(a, b) * b; }
int cdiv(int a, int b) { return (a - 1 + b) / b; }
template <typename T> void fin(T mes) {
  cout << mes << endl;
  exit(0);
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T, typename U> bool chmin(T &a, const U &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &rhs) {
  os << "(" << rhs.first << ", " << rhs.second << ")";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const deque<T> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const map<T, U> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
struct setup {
  static constexpr int PREC = 20;
  setup() {
    cout << fixed << setprecision(PREC);
    cerr << fixed << setprecision(PREC);
  };
} setup;

template <typename M> struct lazy_segment_tree {
  using T = typename M::T;
  using E = typename M::E;
  int n;
  std::vector<T> data;
  std::vector<E> lazy;
  lazy_segment_tree(int n)
      : n(n), data(n << 1, M::id_T()), lazy(n << 1, M::id_E()) {}
  lazy_segment_tree(const std::vector<T> &src)
      : n(src.size()), data(n << 1), lazy(n << 1, M::id_E()) {
    std::copy(src.begin(), src.end(), data.begin() + n);
    for (int i = n - 1; i > 0; i--) {
      data[i] = M::op_TT(data[i << 1 | 0], data[i << 1 | 1]);
    }
  }
  void propagate(int i) {
    if (i < 1) {
      return;
    }
    data[i] = M::op_TE(data[i], lazy[i]);
    if (i < n) {
      lazy[i << 1 | 0] = M::op_EE(lazy[i << 1 | 0], lazy[i]);
      lazy[i << 1 | 1] = M::op_EE(lazy[i << 1 | 1], lazy[i]);
    }
    lazy[i] = M::id_E();
  }
  void add(int l, int r, const E &x) {
    l += n, r += n - 1;
    for (int i = std::__lg(r); i > 0; i--) {
      propagate(l >> i);
      propagate(r >> i);
    }
    auto apply = [&](int i) { lazy[i] = M::op_EE(lazy[i], x), propagate(i); };
    for (int i = l, j = r + 1; i < j; i >>= 1, j >>= 1) {
      if (i & 1) {
        apply(i++);
      }
      if (j & 1) {
        apply(--j);
      }
    }
    while (l >>= 1, r >>= 1) {
      data[l] = M::op_TT(M::op_TE(data[l << 1 | 0], lazy[l << 1 | 0]),
                         M::op_TE(data[l << 1 | 1], lazy[l << 1 | 1]));
      data[r] = M::op_TT(M::op_TE(data[r << 1 | 0], lazy[r << 1 | 0]),
                         M::op_TE(data[r << 1 | 1], lazy[r << 1 | 1]));
    }
  }
  T get_sum(int l, int r) {
    l += n, r += n - 1;
    for (int i = std::__lg(r); i > 0; i--) {
      propagate(l >> i), propagate(r >> i);
    }
    T a = M::id_T(), b = M::id_T();
    for (r++; l < r; l >>= 1, r >>= 1) {
      if (l & 1) {
        propagate(l), a = M::op_TT(a, data[l++]);
      }
      if (r & 1) {
        propagate(--r), b = M::op_TT(data[r], b);
      }
    }
    return M::op_TT(a, b);
  }
};

struct rminq_and_ruq {
  using T = pint;
  using E = int;
  static T id_T() { return {LLONG_MAX, 0}; };
  static E id_E() { return -1; };
  static T op_TT(const T &a, const T &b) {
    if (a.first - a.second < b.first - b.second) {
      return a;
    } else {
      return b;
    }
  }
  static E op_EE(const E &a, const E &b) { return b == id_E() ? a : b; }
  static T op_TE(const T &a, const E &b) {
    return b == id_E() ? a : pint(b, a.second);
  }
};

template <typename F>
long long discrete_binary_search(long long ok, long long ng, F is_ok) {
  while (abs(ok - ng) > 1) {
    long long mid = (ok + ng) / 2;
    (is_ok(mid) ? ok : ng) = mid;
  }
  return ok;
}

signed main() {
  int H, W;
  cin >> H >> W;
  vpint src(W);
  rep(i, W) { src[i] = {i, i}; }
  lazy_segment_tree<rminq_and_ruq> lst(src);
  vint A(H), B(H);
  rep(i, H) {
    cin >> A[i] >> B[i], A[i]--, B[i]--;
    int l = discrete_binary_search(
        W - 1, -1, [&](int x) { return A[i] <= lst.get_sum(x, x + 1).first; });
    int r = discrete_binary_search(
        W, -1, [&](int x) { return B[i] + 1 <= lst.get_sum(x, x + 1).first; });
    if (B[i] == W - 1) {
      lst.add(l, r, LLONG_MAX);
    } else {
      lst.add(l, r, B[i] + 1);
    }
    pint res = lst.get_sum(0, W);
    if (res.first == LLONG_MAX) {
      cout << -1 << endl;
    } else {
      cout << res.first - res.second + i + 1 << endl;
    }
  }
}


Error: TLE

Fixed submission:

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

#define int long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define reps(i, n) for (int i = 1; i <= (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define uniq(x) (x).erase(unique(all(x)), (x).end())
#define bit(n) (1LL << (n))
#define dump(x) cerr << #x " = " << (x) << endl
using vint = vector<int>;
using vvint = vector<vint>;
using pint = pair<int, int>;
using vpint = vector<pint>;
template <typename T>
using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
constexpr double PI = 3.1415926535897932384626433832795028;
constexpr int DY[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
constexpr int DX[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
int sign(int x) { return (x > 0) - (x < 0); }
int gcd(int a, int b) {
  while (b) {
    swap(a %= b, b);
  }
  return a;
}
int lcm(int a, int b) { return a / gcd(a, b) * b; }
int cdiv(int a, int b) { return (a - 1 + b) / b; }
template <typename T> void fin(T mes) {
  cout << mes << endl;
  exit(0);
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T, typename U> bool chmin(T &a, const U &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &rhs) {
  os << "(" << rhs.first << ", " << rhs.second << ")";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const deque<T> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const map<T, U> &rhs) {
  os << "{";
  for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
    os << *itr << (next(itr) != rhs.end() ? ", " : "");
  }
  os << "}";
  return os;
}
struct setup {
  static constexpr int PREC = 20;
  setup() {
    cout << fixed << setprecision(PREC);
    cerr << fixed << setprecision(PREC);
  };
} setup;

template <typename M> struct lazy_segment_tree {
  using T = typename M::T;
  using E = typename M::E;
  int n;
  std::vector<T> data;
  std::vector<E> lazy;
  lazy_segment_tree(int n)
      : n(n), data(n << 1, M::id_T()), lazy(n << 1, M::id_E()) {}
  lazy_segment_tree(const std::vector<T> &src)
      : n(src.size()), data(n << 1), lazy(n << 1, M::id_E()) {
    std::copy(src.begin(), src.end(), data.begin() + n);
    for (int i = n - 1; i > 0; i--) {
      data[i] = M::op_TT(data[i << 1 | 0], data[i << 1 | 1]);
    }
  }
  void propagate(int i) {
    if (i < 1) {
      return;
    }
    data[i] = M::op_TE(data[i], lazy[i]);
    if (i < n) {
      lazy[i << 1 | 0] = M::op_EE(lazy[i << 1 | 0], lazy[i]);
      lazy[i << 1 | 1] = M::op_EE(lazy[i << 1 | 1], lazy[i]);
    }
    lazy[i] = M::id_E();
  }
  void add(int l, int r, const E &x) {
    l += n, r += n - 1;
    for (int i = std::__lg(r); i > 0; i--) {
      propagate(l >> i);
      propagate(r >> i);
    }
    auto apply = [&](int i) { lazy[i] = M::op_EE(lazy[i], x), propagate(i); };
    for (int i = l, j = r + 1; i < j; i >>= 1, j >>= 1) {
      if (i & 1) {
        apply(i++);
      }
      if (j & 1) {
        apply(--j);
      }
    }
    while (l >>= 1, r >>= 1) {
      data[l] = M::op_TT(M::op_TE(data[l << 1 | 0], lazy[l << 1 | 0]),
                         M::op_TE(data[l << 1 | 1], lazy[l << 1 | 1]));
      data[r] = M::op_TT(M::op_TE(data[r << 1 | 0], lazy[r << 1 | 0]),
                         M::op_TE(data[r << 1 | 1], lazy[r << 1 | 1]));
    }
  }
  T get_sum(int l, int r) {
    l += n, r += n - 1;
    for (int i = std::__lg(r); i > 0; i--) {
      propagate(l >> i), propagate(r >> i);
    }
    T a = M::id_T(), b = M::id_T();
    for (r++; l < r; l >>= 1, r >>= 1) {
      if (l & 1) {
        propagate(l), a = M::op_TT(a, data[l++]);
      }
      if (r & 1) {
        propagate(--r), b = M::op_TT(data[r], b);
      }
    }
    return M::op_TT(a, b);
  }
};

struct rminq_and_ruq {
  using T = pint;
  using E = int;
  static T id_T() { return {LLONG_MAX, 0}; };
  static E id_E() { return -1; };
  static T op_TT(const T &a, const T &b) {
    if (a.first - a.second < b.first - b.second) {
      return a;
    } else {
      return b;
    }
  }
  static E op_EE(const E &a, const E &b) { return b == id_E() ? a : b; }
  static T op_TE(const T &a, const E &b) {
    return b == id_E() ? a : pint(b, a.second);
  }
};

template <typename F>
long long discrete_binary_search(long long ok, long long ng, F is_ok) {
  while (abs(ok - ng) > 1) {
    long long mid = (ok + ng) / 2;
    (is_ok(mid) ? ok : ng) = mid;
  }
  return ok;
}

signed main() {
  int H, W;
  cin >> H >> W;
  vpint src(W);
  rep(i, W) { src[i] = {i, i}; }
  lazy_segment_tree<rminq_and_ruq> lst(src);
  vint A(H), B(H);
  rep(i, H) {
    cin >> A[i] >> B[i], A[i]--, B[i]--;
    int l = discrete_binary_search(
        W, -1, [&](int x) { return A[i] <= lst.get_sum(x, x + 1).first; });
    int r = discrete_binary_search(
        W, -1, [&](int x) { return B[i] + 1 <= lst.get_sum(x, x + 1).first; });
    if (B[i] == W - 1) {
      lst.add(l, r, LLONG_MAX);
    } else {
      lst.add(l, r, B[i] + 1);
    }
    pint res = lst.get_sum(0, W);
    if (res.first == LLONG_MAX) {
      cout << -1 << endl;
    } else {
      cout << res.first - res.second + i + 1 << endl;
    }
  }
}