Problem p02551 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;
#ifdef __DEBUG__
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << H;
  debug_out(T...);
}
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

using ll = long long int;
using pii = pair<int, int>;

inline void fast_io() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
};

ll N, Q;
vector<pii> Qs;
inline void input() {
  fast_io();
  cin >> N >> Q;
  for (int i = 0; i < Q; i++) {
    int t, x;
    cin >> t >> x;
    Qs.emplace_back(t, --x);
  }
}

void chmin(int &a, int b) {
  if (a > b)
    a = b;
}

#ifndef ATCODER_LAZYSEGTREE_HPP
#define ATCODER_LAZYSEGTREE_HPP 1

#include <algorithm>

#ifndef ATCODER_INTERNAL_BITOP_HPP
#define ATCODER_INTERNAL_BITOP_HPP 1

#ifdef _MSC_VER
#include <intrin.h>
#endif

namespace atcoder {

namespace internal {

// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
  int x = 0;
  while ((1U << x) < (unsigned int)(n))
    x++;
  return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
  unsigned long index;
  _BitScanForward(&index, n);
  return index;
#else
  return __builtin_ctz(n);
#endif
}

} // namespace internal

} // namespace atcoder

#endif // ATCODER_INTERNAL_BITOP_HPP

#include <cassert>
#include <iostream>
#include <vector>
namespace atcoder {

template <class S, S (*op)(S, S), S (*e)(), class F, S (*mapping)(F, S),
          F (*composition)(F, F), F (*id)()>
struct lazy_segtree {
public:
  lazy_segtree() : lazy_segtree(0) {}
  lazy_segtree(int n) : lazy_segtree(std::vector<S>(n, e())) {}
  lazy_segtree(const std::vector<S> &v) : _n(int(v.size())) {
    log = internal::ceil_pow2(_n);
    size = 1 << log;
    d = std::vector<S>(2 * size, e());
    lz = std::vector<F>(size, id());
    for (int i = 0; i < _n; i++)
      d[size + i] = v[i];
    for (int i = size - 1; i >= 1; i--) {
      update(i);
    }
  }

  void set(int p, S x) {
    assert(0 <= p && p < _n);
    p += size;
    for (int i = log; i >= 1; i--)
      push(p >> i);
    d[p] = x;
    for (int i = 1; i <= log; i++)
      update(p >> i);
  }

  S get(int p) {
    assert(0 <= p && p < _n);
    p += size;
    for (int i = log; i >= 1; i--)
      push(p >> i);
    return d[p];
  }

  S prod(int l, int r) {
    assert(0 <= l && l <= r && r <= _n);
    if (l == r)
      return e();

    l += size;
    r += size;

    for (int i = log; i >= 1; i--) {
      if (((l >> i) << i) != l)
        push(l >> i);
      if (((r >> i) << i) != r)
        push(r >> i);
    }

    S sml = e(), smr = e();
    while (l < r) {
      if (l & 1)
        sml = op(sml, d[l++]);
      if (r & 1)
        smr = op(d[--r], smr);
      l >>= 1;
      r >>= 1;
    }

    return op(sml, smr);
  }

  S all_prod() { return d[1]; }

  void apply(int p, F f) {
    assert(0 <= p && p < _n);
    p += size;
    for (int i = log; i >= 1; i--)
      push(p >> i);
    d[p] = mapping(f, d[p]);
    for (int i = 1; i <= log; i++)
      update(p >> i);
  }
  void apply(int l, int r, F f) {
    assert(0 <= l && l <= r && r <= _n);
    if (l == r)
      return;

    l += size;
    r += size;

    for (int i = log; i >= 1; i--) {
      if (((l >> i) << i) != l)
        push(l >> i);
      if (((r >> i) << i) != r)
        push((r - 1) >> i);
    }

    {
      int l2 = l, r2 = r;
      while (l < r) {
        if (l & 1)
          all_apply(l++, f);
        if (r & 1)
          all_apply(--r, f);
        l >>= 1;
        r >>= 1;
      }
      l = l2;
      r = r2;
    }

    for (int i = 1; i <= log; i++) {
      if (((l >> i) << i) != l)
        update(l >> i);
      if (((r >> i) << i) != r)
        update((r - 1) >> i);
    }
  }

  template <bool (*g)(S)> int max_right(int l) {
    return max_right(l, [](S x) { return g(x); });
  }
  template <class G> int max_right(int l, G g) {
    assert(0 <= l && l <= _n);
    assert(g(e()));
    if (l == _n)
      return _n;
    l += size;
    for (int i = log; i >= 1; i--)
      push(l >> i);
    S sm = e();
    do {
      while (l % 2 == 0)
        l >>= 1;
      if (!g(op(sm, d[l]))) {
        while (l < size) {
          push(l);
          l = (2 * l);
          if (g(op(sm, d[l]))) {
            sm = op(sm, d[l]);
            l++;
          }
        }
        return l - size;
      }
      sm = op(sm, d[l]);
      l++;
    } while ((l & -l) != l);
    return _n;
  }

  template <bool (*g)(S)> int min_left(int r) {
    return min_left(r, [](S x) { return g(x); });
  }
  template <class G> int min_left(int r, G g) {
    assert(0 <= r && r <= _n);
    assert(g(e()));
    if (r == 0)
      return 0;
    r += size;
    for (int i = log; i >= 1; i--)
      push((r - 1) >> i);
    S sm = e();
    do {
      r--;
      while (r > 1 && (r % 2))
        r >>= 1;
      if (!g(op(d[r], sm))) {
        while (r < size) {
          push(r);
          r = (2 * r + 1);
          if (g(op(d[r], sm))) {
            sm = op(d[r], sm);
            r--;
          }
        }
        return r + 1 - size;
      }
      sm = op(d[r], sm);
    } while ((r & -r) != r);
    return 0;
  }

private:
  int _n, size, log;
  std::vector<S> d;
  std::vector<F> lz;

  void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
  void all_apply(int k, F f) {
    d[k] = mapping(f, d[k]);
    if (k < size)
      lz[k] = composition(f, lz[k]);
  }
  void push(int k) {
    all_apply(2 * k, lz[k]);
    all_apply(2 * k + 1, lz[k]);
    lz[k] = id();
  }
};

} // namespace atcoder

#endif // ATCODER_LAZYSEGTREE_HPP

using S = long long;
S op(S x, S y) { return x + y; }
S e() { return 0; }
using F = long long;
S mapping(F f, S x) { return min(f, x); }
F composition(F f, F g) { return min(f, g); }
F id() { return (F)1e9; }

inline int solve() {
  vector<long long> A(N, N - 1);
  atcoder::lazy_segtree<S, op, e, F, mapping, composition, id> row(A),
      column(A);
  ll ans = (N - 2) * (N - 2);

  for (int i = 0; i < Q; i++) {
    int t, x;
    tie(t, x) = Qs[i];
    if (t == 1) {
      // 上に置く
      int r = column.prod(x, x + 1);
      ans -= (r - 1);
      row.apply(0, r + 1, x);
    } else {
      int r = row.prod(x, x + 1);
      ans -= (r - 1);
      column.apply(0, r + 1, x);
    }
  }
  cout << ans << endl;
  return 0;
}

int main() {
  input();
  solve();
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#ifdef __DEBUG__
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << H;
  debug_out(T...);
}
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

using ll = long long int;
using pii = pair<int, int>;

inline void fast_io() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
};

ll N, Q;
vector<pii> Qs;
inline void input() {
  fast_io();
  cin >> N >> Q;
  for (int i = 0; i < Q; i++) {
    int t, x;
    cin >> t >> x;
    Qs.emplace_back(t, --x);
  }
}

void chmin(int &a, int b) {
  if (a > b)
    a = b;
}

inline int solve() {
  vector<int> row(N, N - 1), column(N, N - 1);
  ll ans = (N - 2) * (N - 2);
  for (int i = 0; i < Q; i++) {
    int t, x;
    tie(t, x) = Qs[i];
    if (t == 1) {
      int r = column[x];
      ans -= column[x] - 1;
      column[x] = 0;
      for (int j = 0; j < r; j++) {
        if (x > row[j])
          break;
        chmin(row[j], x);
      }
    } else {
      int r = row[x];
      ans -= row[x] - 1;
      row[x] = 0;
      for (int j = 0; j < r; j++) {
        if (x > column[j])
          break;
        chmin(column[j], x);
      }
    }
  }
  cout << ans << endl;
  return 0;
}

int main() {
  input();
  solve();
  return 0;
}