Problem p02647 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdint>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
using ll = long long;
using ull = unsigned long long;

namespace utils {
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
template <class T, class Compare>
using p_queue = priority_queue<T, vector<T>, Compare>;
template <class T> using min_queue = p_queue<T, greater<T>>;
template <class T> using max_queue = p_queue<T, less<T>>;

template <class T> inline bool UPMIN(T &X, const T &A) {
  if (X > A) {
    X = A;
    return true;
  }
  return false;
}
template <class T> inline bool UPMAX(T &X, const T &A) {
  if (X < A) {
    X = A;
    return true;
  }
  return false;
}

template <class T> vector<T> VEC(int n, T t) { return vector<T>(n, t); }
template <class... Ts> auto VEC(int n, Ts... ts) {
  return vector<decltype(VEC(ts...))>(n, VEC(ts...));
}

template <class S, class T> istream &operator>>(istream &is, tuple<S, T> &t) {
  return is >> get<0>(t) >> get<1>(t);
}

template <class S, class T, class U>
istream &operator>>(istream &is, tuple<S, T, U> &t) {
  return is >> get<0>(t) >> get<1>(t) >> get<2>(t);
}

template <class S, class T>
ostream &operator<<(ostream &os, const tuple<S, T> &t) {
  return os << get<0>(t) << ' ' << get<1>(t);
}

template <class S, class T, class U>
ostream &operator<<(ostream &os, const tuple<S, T, U> &t) {
  return os << get<0>(t) << ' ' << get<1>(t) << ' ' << get<2>(t);
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &&x : v) {
    is >> x;
  }
  return is;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << ' ' << *p++;
  }
  return os;
}

template <class T>
ostream &operator<<(ostream &os, const vector<vector<T>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\\n' << *p++;
  }
  return os;
}

template <class... Ts>
ostream &operator<<(ostream &os, const vector<tuple<Ts...>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\\n' << *p++;
  }
  return os;
}

constexpr long long INFLL = 1'000'000'000'000'000'000ll;
constexpr int INF = 1'000'000'000;
constexpr double PI = 3.14'159'265'358'973;
constexpr double EPS = 1e-10;
} // namespace utils
using namespace utils;

template <class Monoid> class SegmentTree {
  using Func = std::function<Monoid(Monoid, Monoid)>;
  int N;

  std::vector<Monoid> segment, lazy;

  const Func op;
  const Monoid id;

public:
  SegmentTree(int n) : op([](ll a, ll b) { return a + b; }), id(0) {
    N = 1;
    while (N < n)
      N *= 2;
    segment.assign(2 * N, id);
    lazy.assign(2 * N, 0);
  }

  void set(int k, const Monoid &a) { segment[k + N] = a; }

  void build() {
    for (int k = N - 1; k > 0; --k) {
      segment[k] = op(segment[2 * k], segment[2 * k + 1]);
    } // end k
  }

  void eval(int k, int l, int r) {

    if (lazy[k] != 0) {
      segment[k] += lazy[k];
      // 最下段かどうかのチェックをしよう
      // 子ノードは親ノードの 1/2 の範囲であるため、
      // 伝播させるときは半分にする
      if (r - l > 1) {
        lazy[2 * k + 1] += lazy[k] / 2;
        lazy[2 * k + 2] += lazy[k] / 2;
      }

      // 伝播が終わったので、自ノードの遅延配列を空にする
      lazy[k] = 0;
    }
  }

  void update(int k, const Monoid &a) {
    k += N;
    segment[k] = a;
    while (k /= 2) {
      segment[k] = op(segment[k * 2], segment[k * 2 + 1]);
    }
  }

  void update_range(int a, int b, Monoid x, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = N;

    eval(k, l, r);

    // 範囲外なら何もしない
    if (b <= l || r <= a)
      return;

    // 完全に被覆しているならば、遅延配列に値を入れた後に評価
    if (a <= l && r <= b) {
      lazy[k] += (r - l) * x;
      eval(k, l, r);
    }

    // そうでないならば、子ノードの値を再帰的に計算して、
    // 計算済みの値をもらってくる
    else {
      update_range(a, b, x, 2 * k + 1, l, (l + r) / 2);
      update_range(a, b, x, 2 * k + 2, (l + r) / 2, r);
      segment[k] = segment[2 * k + 1] + segment[2 * k + 2];
    }
  }

  // -> op [a,b)
  Monoid query(unsigned a, unsigned b) {
    Monoid L = id, R = id;
    for (a += N, b += N; a < b; a >>= 1u, b >>= 1u) {
      if (a & 1u)
        L = op(L, segment[a++]);
      if (b & 1u)
        R = op(segment[--b], R);
    } // end i
    return op(L, R);
  }

  Monoid operator[](const int &k) const { return segment[k + N]; }
};

class solver {
  istream &is;
  ostream &os;

public:
  solver(istream &I, ostream &O) : is(I), os(O) {}

  ll N, K;
  vector<ll> A;
  bool input() {
    is >> N >> K;
    A.resize(N);
    is >> A;
    return !!is;
  }

  void run();
};

int main(int argc, char *argv[]) {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << setprecision(16) << scientific;
#ifdef XELMH
  string test_cases = "test_C.txt";
  cerr << test_cases << " -->" << endl;
  auto fs = fstream(test_cases, fstream::in);
  int loop = 0;
  while (fs) {
    loop++;
    cout << '#' << loop << "#------\\n";
    solver(fs, cout).run();
  }
  if (loop <= 1) {
    cout << "===" << endl;
    while (cin)
      solver(cin, cout).run();
  }
#else
  solver(cin, cout).run();
#endif
  return 0;
}

void solver::run() {
  if (!input())
    return;
  if (K > 100)
    K = 100;
  while (K > 0) {
    if (*min_element(ALL(A)) == N)
      break;
    //        cout << A << endl;
    auto sum = VEC(N + 1, 0ll);

    for (int i = 0; i < N; ++i) {
      int r = min(N, A[i] + i + 1);
      int l = max(0ll, i - A[i]);
      sum[l]++;
      sum[r]--;
    } // end i
    for (int i = 1; i < sum.size(); ++i) {
      sum[i] += sum[i - 1];
    } // end i
    A = move(sum);
    K--;
  }
  for (int i = 0; i < N; ++i) {
    cout << A[i] << ' ';
  } // end i
}


Error: TLE

Fixed submission:

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdint>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
using ll = long long;
using ull = unsigned long long;

namespace utils {
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
template <class T, class Compare>
using p_queue = priority_queue<T, vector<T>, Compare>;
template <class T> using min_queue = p_queue<T, greater<T>>;
template <class T> using max_queue = p_queue<T, less<T>>;

template <class T> inline bool UPMIN(T &X, const T &A) {
  if (X > A) {
    X = A;
    return true;
  }
  return false;
}
template <class T> inline bool UPMAX(T &X, const T &A) {
  if (X < A) {
    X = A;
    return true;
  }
  return false;
}

template <class T> vector<T> VEC(int n, T t) { return vector<T>(n, t); }
template <class... Ts> auto VEC(int n, Ts... ts) {
  return vector<decltype(VEC(ts...))>(n, VEC(ts...));
}

template <class S, class T> istream &operator>>(istream &is, tuple<S, T> &t) {
  return is >> get<0>(t) >> get<1>(t);
}

template <class S, class T, class U>
istream &operator>>(istream &is, tuple<S, T, U> &t) {
  return is >> get<0>(t) >> get<1>(t) >> get<2>(t);
}

template <class S, class T>
ostream &operator<<(ostream &os, const tuple<S, T> &t) {
  return os << get<0>(t) << ' ' << get<1>(t);
}

template <class S, class T, class U>
ostream &operator<<(ostream &os, const tuple<S, T, U> &t) {
  return os << get<0>(t) << ' ' << get<1>(t) << ' ' << get<2>(t);
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &&x : v) {
    is >> x;
  }
  return is;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << ' ' << *p++;
  }
  return os;
}

template <class T>
ostream &operator<<(ostream &os, const vector<vector<T>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\\n' << *p++;
  }
  return os;
}

template <class... Ts>
ostream &operator<<(ostream &os, const vector<tuple<Ts...>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\\n' << *p++;
  }
  return os;
}

constexpr long long INFLL = 1'000'000'000'000'000'000ll;
constexpr int INF = 1'000'000'000;
constexpr double PI = 3.14'159'265'358'973;
constexpr double EPS = 1e-10;
} // namespace utils
using namespace utils;

template <class Monoid> class SegmentTree {
  using Func = std::function<Monoid(Monoid, Monoid)>;
  int N;

  std::vector<Monoid> segment, lazy;

  const Func op;
  const Monoid id;

public:
  SegmentTree(int n) : op([](ll a, ll b) { return a + b; }), id(0) {
    N = 1;
    while (N < n)
      N *= 2;
    segment.assign(2 * N, id);
    lazy.assign(2 * N, 0);
  }

  void set(int k, const Monoid &a) { segment[k + N] = a; }

  void build() {
    for (int k = N - 1; k > 0; --k) {
      segment[k] = op(segment[2 * k], segment[2 * k + 1]);
    } // end k
  }

  void eval(int k, int l, int r) {

    if (lazy[k] != 0) {
      segment[k] += lazy[k];
      // 最下段かどうかのチェックをしよう
      // 子ノードは親ノードの 1/2 の範囲であるため、
      // 伝播させるときは半分にする
      if (r - l > 1) {
        lazy[2 * k + 1] += lazy[k] / 2;
        lazy[2 * k + 2] += lazy[k] / 2;
      }

      // 伝播が終わったので、自ノードの遅延配列を空にする
      lazy[k] = 0;
    }
  }

  void update(int k, const Monoid &a) {
    k += N;
    segment[k] = a;
    while (k /= 2) {
      segment[k] = op(segment[k * 2], segment[k * 2 + 1]);
    }
  }

  void update_range(int a, int b, Monoid x, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = N;

    eval(k, l, r);

    // 範囲外なら何もしない
    if (b <= l || r <= a)
      return;

    // 完全に被覆しているならば、遅延配列に値を入れた後に評価
    if (a <= l && r <= b) {
      lazy[k] += (r - l) * x;
      eval(k, l, r);
    }

    // そうでないならば、子ノードの値を再帰的に計算して、
    // 計算済みの値をもらってくる
    else {
      update_range(a, b, x, 2 * k + 1, l, (l + r) / 2);
      update_range(a, b, x, 2 * k + 2, (l + r) / 2, r);
      segment[k] = segment[2 * k + 1] + segment[2 * k + 2];
    }
  }

  // -> op [a,b)
  Monoid query(unsigned a, unsigned b) {
    Monoid L = id, R = id;
    for (a += N, b += N; a < b; a >>= 1u, b >>= 1u) {
      if (a & 1u)
        L = op(L, segment[a++]);
      if (b & 1u)
        R = op(segment[--b], R);
    } // end i
    return op(L, R);
  }

  Monoid operator[](const int &k) const { return segment[k + N]; }
};

class solver {
  istream &is;
  ostream &os;

public:
  solver(istream &I, ostream &O) : is(I), os(O) {}

  ll N, K;
  vector<ll> A;
  bool input() {
    is >> N >> K;
    A.resize(N);
    is >> A;
    return !!is;
  }

  void run();
};

int main(int argc, char *argv[]) {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << setprecision(16) << scientific;
#ifdef XELMH
  string test_cases = "test_C.txt";
  cerr << test_cases << " -->" << endl;
  auto fs = fstream(test_cases, fstream::in);
  int loop = 0;
  while (fs) {
    loop++;
    cout << '#' << loop << "#------\\n";
    solver(fs, cout).run();
  }
  if (loop <= 1) {
    cout << "===" << endl;
    while (cin)
      solver(cin, cout).run();
  }
#else
  solver(cin, cout).run();
#endif
  return 0;
}

void solver::run() {
  if (!input())
    return;
  while (K > 0) {
    if (*min_element(ALL(A)) == N)
      break;
    //        cout << A << endl;
    auto sum = VEC(N + 1, 0ll);

    for (int i = 0; i < N; ++i) {
      int r = min(N, A[i] + i + 1);
      int l = max(0ll, i - A[i]);
      sum[l]++;
      sum[r]--;
    } // end i
    for (int i = 1; i < sum.size(); ++i) {
      sum[i] += sum[i - 1];
    } // end i
    A = move(sum);
    K--;
  }
  for (int i = 0; i < N; ++i) {
    cout << A[i] << ' ';
  } // end i
}