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

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n) for (ll i = 0; i < (ll)n; i++)
#define REPR(i, n) for (ll i = (ll)n - 1; i >= 0; i--)
#define FOR(i, m, n) for (ll i = (ll)m; i < (ll)n; i++)
#define FORR(i, m, n) for (ll i = (ll)m - 1; i >= (ll)n; i--)
#define ALL(x) (x).begin(), (x).end()
#define ASC(v) sort(ALL(v));
#define DESC(v) sort(ALL(v), greater<int>());
#define UNIQ(a)                                                                \\
  sort(ALL(a));                                                                \\
  (a).resize(unique(ALL(a)) - a.begin());
#define PRINTD(x, d) cout << fixed << setprecision(d) << x << "\\n";
#define DEBUG(x) cout << #x << ": " << x << "\\n"
const double PI = acos(-1);
ll lcm(ll a, ll b) { return a / __gcd(a, b) * b; }
bool isprime(int x) {
  int i;
  if (x < 2)
    return 0;
  else if (x == 2)
    return 1;
  if (x % 2 == 0)
    return 0;
  for (i = 3; i * i <= x; i += 2)
    if (x % i == 0)
      return 0;
  return 1;
}
int digsum(int n) {
  int r = 0;
  while (n > 0) {
    r += n % 10;
    n /= 10;
  }
  return r;
}
vector<string> split(string s, char p) {
  vector<string> v;
  stringstream m(s);
  string b;
  while (getline(m, b, p))
    v.push_back(b);
  return v;
}
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 (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct nya {
  nya() {
    cin.tie(0);
    ios::sync_with_stdio(false);
  }
} nyan;

int main() {
  ll N, K;
  cin >> N >> K;
  vector<ll> A(N + 1);
  FOR(i, 1, N + 1) cin >> A[i];
  REP(k, K) {
    vector<ll> B(N + 1, 0);
    bool isALLN = true;
    FOR(n, 1, N + 1) {
      if (A[n] != N)
        isALLN = false;
      ll l = max(0, (int)n - (int)A[n]);
      ll r = min(N, n + A[n]);
      B[l]++;
      if (r + 1 < N + 1)
        B[r + 1]--;
    }
    FOR(n, 1, N + 1) B[n] += B[n - 1];
    A = B;
    if (isALLN)
      break;
  }
  FOR(n, 1, N + 1) { cout << A[n] << " "; }
  cout << "\\n";
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n) for (ll i = 0; i < (ll)n; i++)
#define REPR(i, n) for (ll i = (ll)n - 1; i >= 0; i--)
#define FOR(i, m, n) for (ll i = (ll)m; i < (ll)n; i++)
#define FORR(i, m, n) for (ll i = (ll)m - 1; i >= (ll)n; i--)
#define ALL(x) (x).begin(), (x).end()
#define ASC(v) sort(ALL(v));
#define DESC(v) sort(ALL(v), greater<int>());
#define UNIQ(a)                                                                \\
  sort(ALL(a));                                                                \\
  (a).resize(unique(ALL(a)) - a.begin());
#define PRINTD(x, d) cout << fixed << setprecision(d) << x << "\\n";
#define DEBUG(x) cout << #x << ": " << x << "\\n"
const double PI = acos(-1);
ll lcm(ll a, ll b) { return a / __gcd(a, b) * b; }
bool isprime(int x) {
  int i;
  if (x < 2)
    return 0;
  else if (x == 2)
    return 1;
  if (x % 2 == 0)
    return 0;
  for (i = 3; i * i <= x; i += 2)
    if (x % i == 0)
      return 0;
  return 1;
}
int digsum(int n) {
  int r = 0;
  while (n > 0) {
    r += n % 10;
    n /= 10;
  }
  return r;
}
vector<string> split(string s, char p) {
  vector<string> v;
  stringstream m(s);
  string b;
  while (getline(m, b, p))
    v.push_back(b);
  return v;
}
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 (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct nya {
  nya() {
    cin.tie(0);
    ios::sync_with_stdio(false);
  }
} nyan;

int main() {
  ll N, K;
  cin >> N >> K;
  vector<ll> A(N + 1);
  FOR(i, 1, N + 1) cin >> A[i];
  REP(k, K) {
    vector<ll> dp(N + 1, 0);
    bool isALLN = true;
    FOR(n, 1, N + 1) {
      if (A[n] != N)
        isALLN = false;
      FOR(i, n - A[n], n - A[n] + A[n] * 2 + 1) {
        if (i < 1 || N < i)
          continue;
        dp[i]++;
      }
    }
    A = dp;
    if (isALLN)
      break;
  }
  FOR(n, 1, N + 1) { cout << A[n] << " "; }
  cout << "\\n";
}