Problem p02647 (C++) — buggy submission, verdict: Runtime Error

// #include <tourist>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> p;
const int INF = 1e9;
const ll LINF = ll(1e18);
const int MOD = 1000000007;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0};
const int Dx[8] = {0, 1, 1, 1, 0, -1, -1, -1},
          Dy[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
#define yes cout << "Yes" << endl
#define YES cout << "YES" << endl
#define no cout << "No" << endl
#define NO cout << "NO" << endl
#define rep(i, n) for (int i = 0; i < n; i++)
#define ALL(v) v.begin(), v.end()
#define debug(v)                                                               \\
  cout << #v << ":";                                                           \\
  for (auto x : v) {                                                           \\
    cout << x << ' ';                                                          \\
  }                                                                            \\
  cout << endl;
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;
}
// cout<<fixed<<setprecision(15);有効数字15桁
//-std=c++14
//-std=gnu++17
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
int n, k;
vector<int> a;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n >> k;
  a.resize(n);
  rep(i, n) cin >> a[i];
  rep(i, min(k, 100)) {
    vector<int> count(n + 1, 0);
    rep(j, n) {
      if (j - a[j] < 0)
        count[0]++;
      else
        count[j - a[j]]++;
      if (j + a[j] + 1 > n)
        count[n]--;
      else
        count[j + a[j] + 1]--;
    }
    int sum = 0;
    rep(j, n) {
      sum += count[j];
      a[j] = sum;
    }
  }
  rep(i, n) cout << a[i] << " ";
  cout << "\\n";
}


Error: WA

Fixed submission:

// #include <tourist>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> p;
const int INF = 1e9;
const ll LINF = ll(1e18);
const int MOD = 1000000007;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0};
const int Dx[8] = {0, 1, 1, 1, 0, -1, -1, -1},
          Dy[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
#define yes cout << "Yes" << endl
#define YES cout << "YES" << endl
#define no cout << "No" << endl
#define NO cout << "NO" << endl
#define rep(i, n) for (int i = 0; i < n; i++)
#define ALL(v) v.begin(), v.end()
#define debug(v)                                                               \\
  cout << #v << ":";                                                           \\
  for (auto x : v) {                                                           \\
    cout << x << ' ';                                                          \\
  }                                                                            \\
  cout << endl;
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;
}
// cout<<fixed<<setprecision(15);有効数字15桁
//-std=c++14
//-std=gnu++17
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
int n, k;
vector<int> a;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n >> k;
  a.resize(n);
  rep(i, n) cin >> a[i];
  rep(i, min(k, 100)) {
    vector<int> count(n + 1, 0);
    rep(j, n) {
      if (j - a[j] < 0)
        count[0]++;
      else
        count[j - a[j]]++;
      if (j + a[i] + 1 > n)
        count[n]--;
      else
        count[j + a[j] + 1]--;
    }
    int sum = 0;
    rep(j, n) {
      sum += count[j];
      a[j] = sum;
    }
  }
  rep(i, n) cout << a[i] << " ";
  cout << "\\n";
}