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

#include <algorithm>
#include <complex>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define REP(i, m, n) for (int i = int(m); i < int(n); i++)
#define RREP(i, m, n) for (int i = int(n) - 1; i >= int(m); --i)
#define EACH(i, c) for (auto &(i) : c)
#define all(c) begin(c), end(c)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort(begin(c), end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())
// #define int long long

#ifdef LOCAL
#define DEBUG(s) cout << (s) << endl
#define dump(x) cerr << #x << " = " << (x) << endl
#define BR cout << endl;
#else
#define DEBUG(s)                                                               \\
  do {                                                                         \\
  } while (0)
#define dump(x)                                                                \\
  do {                                                                         \\
  } while (0)
#define BR
#endif
using namespace std;

using UI = unsigned int;
using UL = unsigned long;
using LL = long long;
using ULL = unsigned long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VLL = vector<LL>;
using VVLL = vector<VLL>;
using VS = vector<string>;
using PII = pair<int, int>;
using VP = vector<PII>;
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

void solve() {
  LL n, k;
  cin >> n >> k;
  VLL a(n);
  REP(i, 0, n) cin >> a[i];
  VI imos(n + 1);
  REP(j, 0, k) {
    REP(i, 0, n + 1) imos[i] = 0;
    REP(i, 0, n) {
      imos[max(0LL, i - a[i])]++;
      imos[min(n, i + a[i] + 1)]--;
    }
    REP(i, 1, n + 1) imos[i] += imos[i - 1];
    REP(i, 0, n) a[i] = imos[i];
    bool done = true;
    REP(i, 0, n) if (a[i] < n) {
      done = false;
      break;
    }
    if (done)
      break;
  }
  REP(i, 0, n) cout << a[i] << " ";
  cout << endl;
}

signed main() {
  solve();

  return 0;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <complex>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define REP(i, m, n) for (int i = int(m); i < int(n); i++)
#define RREP(i, m, n) for (int i = int(n) - 1; i >= int(m); --i)
#define EACH(i, c) for (auto &(i) : c)
#define all(c) begin(c), end(c)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort(begin(c), end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())
// #define int long long

#ifdef LOCAL
#define DEBUG(s) cout << (s) << endl
#define dump(x) cerr << #x << " = " << (x) << endl
#define BR cout << endl;
#else
#define DEBUG(s)                                                               \\
  do {                                                                         \\
  } while (0)
#define dump(x)                                                                \\
  do {                                                                         \\
  } while (0)
#define BR
#endif
using namespace std;

using UI = unsigned int;
using UL = unsigned long;
using LL = long long;
using ULL = unsigned long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VLL = vector<LL>;
using VVLL = vector<VLL>;
using VS = vector<string>;
using PII = pair<int, int>;
using VP = vector<PII>;
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

void solve() {
  LL n, k;
  cin >> n >> k;
  VLL a(n);
  REP(i, 0, n) cin >> a[i];
  VI imos(n + 1);
  REP(j, 0, k) {
    REP(i, 0, n + 1) imos[i] = 0;
    REP(i, 0, n) {
      imos[max(0LL, i - a[i])]++;
      imos[min(n, i + a[i] + 1)]--;
    }
    REP(i, 1, n + 1) imos[i] += imos[i - 1];
    REP(i, 0, n) a[i] = imos[i];
  }
  REP(i, 0, n) cout << a[i] << " ";
  cout << endl;
}

signed main() {
  solve();

  return 0;
}