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

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

// 型定義
typedef long long ll;

// 定数
const int INF = 1e+9;
const int MOD = 1e+9 + 7;

// REPマクロ
#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
#define REPD(i, n) for (ll i = n - 1; i >= 0; i--)
#define REP2(i, a, b) for (ll i = a; i < (ll)(b); i++)
#define REPD2(i, a, b) for (ll i = a; i > (ll)(b); i--)

// 多次元 vector 生成
template <class T> vector<T> make_vec(size_t a) { return vector<T>(a); }
template <class T, class... Ts> auto make_vec(size_t a, Ts... ts) {
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}

// vectorの扱い
#define ALL(x) (x).begin(), (x).end() // sortなどの引数省略
#define SIZE(x) ((ll)(x).size())      // size
#define MAX(x) *max_element(ALL(x))   // 最大値
#define MIN(x) *min_element(ALL(x))   // 最小値
struct LazySegmentTree {
private:
  int n;
  vector<ll> node, lazy;

public:
  LazySegmentTree(vector<ll> v) {
    int sz = (int)v.size();
    n = 1;
    while (n < sz)
      n *= 2;
    node.resize(2 * n - 1);
    lazy.resize(2 * n - 1, 0);

    for (int i = 0; i < sz; i++)
      node[i + n - 1] = v[i];
    for (int i = n - 2; i >= 0; i--)
      node[i] = node[i * 2 + 1] + node[i * 2 + 2];
  }

  void eval(int k, int l, int r) {
    if (lazy[k] != 0) {
      node[k] += lazy[k];
      if (r - l > 1) {
        lazy[2 * k + 1] += lazy[k] / 2;
        lazy[2 * k + 2] += lazy[k] / 2;
      }
      lazy[k] = 0;
    }
  }

  void add(int a, int b, ll x, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = n;
    eval(k, l, r);
    if (b <= l || r <= a)
      return;
    if (a <= l && r <= b) {
      lazy[k] += (r - l) * x;
      eval(k, l, r);
    } else {
      add(a, b, x, 2 * k + 1, l, (l + r) / 2);
      add(a, b, x, 2 * k + 2, (l + r) / 2, r);
      node[k] = node[2 * k + 1] + node[2 * k + 2];
    }
  }

  ll getsum(int a, int b, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = n;
    eval(k, l, r);
    if (b <= l || r <= a)
      return 0;
    if (a <= l && r <= b)
      return node[k];
    ll vl = getsum(a, b, 2 * k + 1, l, (l + r) / 2);
    ll vr = getsum(a, b, 2 * k + 2, (l + r) / 2, r);
    return vl + vr;
  }

  ll get(int n) { return node[n]; }
};

int main() {
  ll N, K;
  cin >> N >> K;
  vector<ll> A(N, 0);
  REP(i, N) cin >> A[i];

  REP(i, K) {
    vector<ll> table(N + 1, 0);
    REP(j, N) {
      table[max((ll)0, j - A[j])]++;
      table[min(j + A[j] + 1, N)]--;
    }
    REP2(j, 1, N) table[j] += table[j - 1];

    ll ans = INF;
    REP(j, N) {
      A[j] = table[j];
      ans = min(ans, A[j]);
    }
    if (ans == N)
      break;
  }

  REP(i, N) { cout << A[i] << " "; }
  cout << endl;
}

Error: TLE

Fixed submission:

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

// 型定義
typedef long long ll;

// 定数
const int INF = 1e+9;
const int MOD = 1e+9 + 7;

// REPマクロ
#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
#define REPD(i, n) for (ll i = n - 1; i >= 0; i--)
#define REP2(i, a, b) for (ll i = a; i < (ll)(b); i++)
#define REPD2(i, a, b) for (ll i = a; i > (ll)(b); i--)

// 多次元 vector 生成
template <class T> vector<T> make_vec(size_t a) { return vector<T>(a); }
template <class T, class... Ts> auto make_vec(size_t a, Ts... ts) {
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}

// vectorの扱い
#define ALL(x) (x).begin(), (x).end() // sortなどの引数省略
#define SIZE(x) ((ll)(x).size())      // size
#define MAX(x) *max_element(ALL(x))   // 最大値
#define MIN(x) *min_element(ALL(x))   // 最小値
struct LazySegmentTree {
private:
  int n;
  vector<ll> node, lazy;

public:
  LazySegmentTree(vector<ll> v) {
    int sz = (int)v.size();
    n = 1;
    while (n < sz)
      n *= 2;
    node.resize(2 * n - 1);
    lazy.resize(2 * n - 1, 0);

    for (int i = 0; i < sz; i++)
      node[i + n - 1] = v[i];
    for (int i = n - 2; i >= 0; i--)
      node[i] = node[i * 2 + 1] + node[i * 2 + 2];
  }

  void eval(int k, int l, int r) {
    if (lazy[k] != 0) {
      node[k] += lazy[k];
      if (r - l > 1) {
        lazy[2 * k + 1] += lazy[k] / 2;
        lazy[2 * k + 2] += lazy[k] / 2;
      }
      lazy[k] = 0;
    }
  }

  void add(int a, int b, ll x, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = n;
    eval(k, l, r);
    if (b <= l || r <= a)
      return;
    if (a <= l && r <= b) {
      lazy[k] += (r - l) * x;
      eval(k, l, r);
    } else {
      add(a, b, x, 2 * k + 1, l, (l + r) / 2);
      add(a, b, x, 2 * k + 2, (l + r) / 2, r);
      node[k] = node[2 * k + 1] + node[2 * k + 2];
    }
  }

  ll getsum(int a, int b, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = n;
    eval(k, l, r);
    if (b <= l || r <= a)
      return 0;
    if (a <= l && r <= b)
      return node[k];
    ll vl = getsum(a, b, 2 * k + 1, l, (l + r) / 2);
    ll vr = getsum(a, b, 2 * k + 2, (l + r) / 2, r);
    return vl + vr;
  }
};

int main() {
  ll N, K;
  cin >> N >> K;
  vector<ll> A(N + 1, 0);
  REP(i, N) cin >> A[i + 1];

  REP(i, K) {
    LazySegmentTree seg(vector<ll>(N, 0));
    vector<ll> B(N, 0);
    REP2(j, 1, N + 1) {
      seg.add(j - A[j] - 1, j + A[j], 1);
      // REP2(k,max((ll)0,j-A[j]),min(N,j+A[j]+1)){
      //     B[k]++;
      // }
    }
    ll ans = INF;
    REP2(j, 1, N + 1) {
      ans = min(ans, B[j]);
      A[j] = seg.getsum(j - 1, j);
    }
    if (ans >= N)
      break;
  }

  REP2(i, 1, N + 1) { cout << A[i] << " "; }
  cout << endl;
}