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

#include <bits/stdc++.h>
#define LOCAL
using namespace std;
template <typename A, typename B>
ostream &operator<<(ostream &out, const pair<A, B> &a) {
  out << "(" << a.first << "," << a.second << ")";
  return out;
}
template <typename T, size_t N>
ostream &operator<<(ostream &out, const array<T, N> &a) {
  out << "[";
  bool first = true;
  for (auto &v : a) {
    out << (first ? "" : ", ");
    out << v;
    first = 0;
  }
  out << "]";
  return out;
}
template <typename T> ostream &operator<<(ostream &out, const vector<T> &a) {
  out << "[";
  bool first = true;
  for (auto &v : a) {
    out << (first ? "" : ", ");
    out << v;
    first = 0;
  }
  out << "]";
  return out;
}
template <typename T, class Cmp>
ostream &operator<<(ostream &out, const set<T, Cmp> &a) {
  out << "{";
  bool first = true;
  for (auto &v : a) {
    out << (first ? "" : ", ");
    out << v;
    first = 0;
  }
  out << "}";
  return out;
}
template <typename U, typename T, class Cmp>
ostream &operator<<(ostream &out, const map<U, T, Cmp> &a) {
  out << "{";
  bool first = true;
  for (auto &p : a) {
    out << (first ? "" : ", ");
    out << p.first << ":" << p.second;
    first = 0;
  }
  out << "}";
  return out;
}
#ifdef LOCAL
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
#else
#define trace(...) 42
#endif
template <typename Arg1> void __f(const char *name, Arg1 &&arg1) {
  cerr << name << ": " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char *names, Arg1 &&arg1, Args &&...args) {
  const char *comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << ": " << arg1 << " |";
  __f(comma + 1, args...);
}
#define rep(i, n) for (int i = 0; i < (n); i++)
using ll = long long;
#define int long long
using P = pair<int, int>;
// #########################################

signed main() {
  int n, k;
  cin >> n >> k;
  int a[n + 1];

  rep(i, n) { cin >> a[i + 1]; }
  vector<int> lamp(n + 100);
  if (n * k >= 10000000) {
    rep(i, n) cout << n << endl;
    return 0;
  }

  rep(j, k) {
    bool end = true;
    rep(i, n) {
      int l = max((i + 1) - a[i + 1], 1ll);
      int r = min((i + 1) + a[i + 1] + 1, n + 1);
      if (l != 1 || r != n)
        end = false;
      lamp[l]++;
      lamp[r]--;
    }
    if (end) {
      rep(i, n) cout << n << endl;
      return 0;
    }

    rep(i, n) {
      // trace(lamp[i],i);
      lamp[i + 1] += lamp[i];
      a[i + 1] = lamp[i + 1];
      // trace(a[i+1],i+1);
    }
    if (j != k - 1)
      rep(i, n + 1) lamp[i] = 0;
  }
  rep(i, n) cout << lamp[i + 1] << endl;
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#define LOCAL
using namespace std;
template <typename A, typename B>
ostream &operator<<(ostream &out, const pair<A, B> &a) {
  out << "(" << a.first << "," << a.second << ")";
  return out;
}
template <typename T, size_t N>
ostream &operator<<(ostream &out, const array<T, N> &a) {
  out << "[";
  bool first = true;
  for (auto &v : a) {
    out << (first ? "" : ", ");
    out << v;
    first = 0;
  }
  out << "]";
  return out;
}
template <typename T> ostream &operator<<(ostream &out, const vector<T> &a) {
  out << "[";
  bool first = true;
  for (auto &v : a) {
    out << (first ? "" : ", ");
    out << v;
    first = 0;
  }
  out << "]";
  return out;
}
template <typename T, class Cmp>
ostream &operator<<(ostream &out, const set<T, Cmp> &a) {
  out << "{";
  bool first = true;
  for (auto &v : a) {
    out << (first ? "" : ", ");
    out << v;
    first = 0;
  }
  out << "}";
  return out;
}
template <typename U, typename T, class Cmp>
ostream &operator<<(ostream &out, const map<U, T, Cmp> &a) {
  out << "{";
  bool first = true;
  for (auto &p : a) {
    out << (first ? "" : ", ");
    out << p.first << ":" << p.second;
    first = 0;
  }
  out << "}";
  return out;
}
#ifdef LOCAL
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
#else
#define trace(...) 42
#endif
template <typename Arg1> void __f(const char *name, Arg1 &&arg1) {
  cerr << name << ": " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char *names, Arg1 &&arg1, Args &&...args) {
  const char *comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << ": " << arg1 << " |";
  __f(comma + 1, args...);
}
#define rep(i, n) for (int i = 0; i < (n); i++)
using ll = long long;
#define int long long
using P = pair<int, int>;
// #########################################

signed main() {
  int n, k;
  cin >> n >> k;
  int a[n + 1];

  rep(i, n) { cin >> a[i + 1]; }
  vector<int> lamp(n + 100);
  if (k >= n * 100) {
    rep(i, n) cout << n << endl;
    return 0;
  }

  rep(j, k) {
    bool end = true;
    rep(i, n) {
      int l = max((i + 1) - a[i + 1], 1ll);
      int r = min((i + 1) + a[i + 1] + 1, n + 1);
      if (l != 1 || r != n)
        end = false;
      lamp[l]++;
      lamp[r]--;
    }
    if (end) {
      rep(i, n) cout << n << endl;
      return 0;
    }

    rep(i, n) {
      // trace(lamp[i],i);
      lamp[i + 1] += lamp[i];
      a[i + 1] = lamp[i + 1];
      // trace(a[i+1],i+1);
    }
    if (j != k - 1)
      rep(i, n + 1) lamp[i] = 0;
  }
  rep(i, n) cout << lamp[i + 1] << endl;
  return 0;
}