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

#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORR(i, a, b) for (ll i = (a); i <= (b); i++)
#define repR(i, n) for (ll i = n; i >= 0; i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout << (x) << "\\n"
#define PQ priority_queue<ll>
#define PQR priority_queue<ll, vector<ll>, greater<ll>>
#define YES(n) cout << ((n) ? "YES\\n" : "NO\\n")
#define Yes(n) cout << ((n) ? "Yes\\n" : "No\\n")
#define mp make_pair
#define sz(x) (ll)(x).size()
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using vc = vector<char>;
using vvc = vector<vc>;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll dx[4] = {0, 1, 0, -1};
ll dy[4] = {1, 0, -1, 0};
int main() {
  ll n, k;
  cin >> n >> k;
  vll a(n + 1);
  rep(i, n) cin >> a[i];
  while (k) {
    k--;
    vll b(n + 1);
    rep(i, n) {
      b[max(0LL, i - a[i])]++;
      b[min(n, i + a[i] + 1)]--;
    }
    rep(i, n + 1) {
      if (i == 0)
        continue;
      b[i] += b[i - 1];
    }
    if (a == b)
      break;
    a = b;
  }
  rep(i, n) { cout << a[i] << " "; }
}

Error: -6
munmap_chunk(): invalid pointer


Fixed submission:

#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORR(i, a, b) for (ll i = (a); i <= (b); i++)
#define repR(i, n) for (ll i = n; i >= 0; i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout << (x) << "\\n"
#define PQ priority_queue<ll>
#define PQR priority_queue<ll, vector<ll>, greater<ll>>
#define YES(n) cout << ((n) ? "YES\\n" : "NO\\n")
#define Yes(n) cout << ((n) ? "Yes\\n" : "No\\n")
#define mp make_pair
#define sz(x) (ll)(x).size()
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using vc = vector<char>;
using vvc = vector<vc>;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll dx[4] = {0, 1, 0, -1};
ll dy[4] = {1, 0, -1, 0};
int main() {
  ll n, k;
  cin >> n >> k;
  vll a(n + 1);
  rep(i, n) cin >> a[i];
  while (k) {
    k--;
    vll b(n + 1);
    rep(i, n) {
      b[min(0LL, i - a[i])]++;
      b[min(n, i + a[i] + 1)]--;
    }
    rep(i, n + 1) {
      if (i == 0)
        continue;
      b[i] -= b[i - 1];
    }
    if (a == b)
      break;
    a = b;
  }
  rep(i, n) { cout << a[i] << " "; }
}