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

#include <bits/stdc++.h>
using namespace std;

#define INF_LL (int64)1e18
#define INF (int32)1e9
#define REP(i, n) for (int64 i = 0; i < (n); i++)
#define FOR(i, a, b) for (int64 i = (a); i < (b); i++)
#define all(x) x.begin(), x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template <typename A, typename B> inline void chmin(A &a, B b) {
  if (a > b)
    a = b;
}
template <typename A, typename B> inline void chmax(A &a, B b) {
  if (a < b)
    a = b;
}

template <typename T> vector<T> make_v(size_t a) { return vector<T>(a); }

template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value != 0>::type fill_v(U &u, const V... v) {
  u = U(v...);
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value == 0>::type fill_v(U &u, const V... v) {
  for (auto &e : u)
    fill_v<T>(e, v...);
}

bool proceed(vector<int64> &A) {
  int mini = INF;
  vector<int64> B(A.size(), 0);
  REP(i, A.size()) {
    int64 l = max((int64)0, i - A[i]);
    int64 r = min((int64)A.size(), i + A[i] + 1);
    B[l]++;
    if (r < B.size())
      B[r]--;
  }
  REP(i, B.size()) {
    if (i > 0)
      B[i] += B[i - 1];
    chmin(mini, B[i]);
  }
  swap(A, B);
  return mini == B.size();
}

int main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int64 N, K;
  cin >> N >> K;
  vector<int64> A(N);
  REP(i, N) { cin >> A[i]; }
  REP(i, K) {
    if (proceed(A))
      break;
  }
  REP(i, N) { cout << A[i] << " "; }
  cout << endl;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

#define INF_LL (int64)1e18
#define INF (int32)1e9
#define REP(i, n) for (int64 i = 0; i < (n); i++)
#define FOR(i, a, b) for (int64 i = (a); i < (b); i++)
#define all(x) x.begin(), x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template <typename A, typename B> inline void chmin(A &a, B b) {
  if (a > b)
    a = b;
}
template <typename A, typename B> inline void chmax(A &a, B b) {
  if (a < b)
    a = b;
}

template <typename T> vector<T> make_v(size_t a) { return vector<T>(a); }

template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value != 0>::type fill_v(U &u, const V... v) {
  u = U(v...);
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value == 0>::type fill_v(U &u, const V... v) {
  for (auto &e : u)
    fill_v<T>(e, v...);
}

bool proceed(vector<int64> &A) {
  int mini = INF;
  vector<int64> B(A.size(), 0);
  REP(i, A.size()) {
    FOR(j, max((int64)0, i - A[i]), min((int64)A.size(), i + A[i] + 1)) {
      B[j]++;
    }
  }
  REP(i, B.size()) { chmin(mini, B[i]); }
  swap(A, B);
  return mini == B.size();
}

int main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int64 N, K;
  cin >> N >> K;
  vector<int64> A(N);
  REP(i, N) { cin >> A[i]; }
  REP(i, K) {
    if (proceed(A))
      break;
  }
  REP(i, N) { cout << A[i] << " "; }
  cout << endl;
}