Problem p03176 (C++)

Buggy submission (status: Runtime Error):
/*░   ░▄▀▀▀▄░Prashik░░
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#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define M 1000000007
#define fastio                                                                 \
  ios_base::sync_with_stdio(false);                                            \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define endl "\n"
#define all(x) (x).begin(), (x).end()
#define tr(x, it) for (auto it = x.begin(); it != x.end(); ++it)
#define fpresent(x, c) ((c).find(x) != (c).end())    // set,map
#define present(c, x) (find(all(c), x) != (c).end()) // vector
#define pb push_back
#define mp make_pair
#define setv(ar, val) memset(ar, val, sizeof(ar));
#define error(args...)                                                         \
  {                                                                            \
    string _s = #args;                                                         \
    replace(_s.begin(), _s.end(), ',', ' ');                                   \
    stringstream _ss(_s);                                                      \
    istream_iterator<string> _it(_ss);                                         \
    err(_it, args);                                                            \
  }
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  err(++it, args...);
}

vector<ll> tree(100000);

ll n;

void buildtree(ll a[], ll node, ll left, ll right) {
  if (left == right) {
    tree[node] = a[left];
  } else {
    ll mid = (left + right) / 2;
    buildtree(a, 2 * node + 1, left, mid);
    buildtree(a, 2 * node + 2, mid + 1, right);
    tree[node] =
        max(tree[2 * node + 1],
            tree[2 * node +
                 2]); // this tree is for the sum in the given range query ,
                      // this line can be modified according to the need for
                      // example, if we have to find the minimum in the given
                      // range we can accordingly change the line of command;
  }
}
void updateutil(
    ll a[], ll x, ll pos, ll left, ll right,
    ll node) // give the val to be updated and the pos where to update. pos
             // should be with respect to the original array.
{
  if (left == right) {
    a[pos] = x;
    tree[node] = x;
  } else {
    ll mid = (left + right) / 2;
    if (pos <= mid) {
      updateutil(a, x, pos, left, mid, 2 * node + 1);
    } else
      updateutil(a, x, pos, mid + 1, right, 2 * node + 2);
    tree[node] = max(tree[2 * node + 1],
                     tree[2 * node + 2]); // this line can be changed
                                          // accordingly for a different query
  }
}
void update(ll a[], ll x, ll pos) { updateutil(a, x, pos - 1, 0, n - 1, 0); }
void prlltree() {
  for (ll i = 0; i < 2 * n - 1; i++)
    cout << tree[i] << endl;
}
ll queryutil(ll left, ll right, ll l, ll r, ll node) {

  if (left == l && right == r) {
    return tree[node];
  } else {
    if (left <= right) {
      ll mid = (l + r) / 2;
      if (mid >= right) {
        return queryutil(left, right, l, mid, 2 * node + 1);
      }
      if (left > mid) {
        return queryutil(left, right, mid + 1, r, 2 * node + 2);
      }
      if (left <= mid && right > mid) {
        return max(queryutil(left, mid, l, mid, 2 * node + 1),
                   queryutil(mid + 1, right, mid + 1, r,
                             2 * node + 2)); // this line can be changed for
                                             // minimum or maximum query
      }
    } else
      return 0;
  }
}
ll query(ll left, ll right) {
  return queryutil(left - 1, right - 1, 0, n - 1, 0);
}

int main() {
  // freopen("input.in","r",stdin);
  // freopen("output.in","w",stdout);
  fastio;
  cin.tie(NULL);
  ll m, i, j, k, ans = 0;
  cin >> n;
  ll h[n], a[n], rev[n + 1];
  for (i = 0; i < n; i++) {
    cin >> h[i];
    rev[h[i]] = i;
  }
  for (i = 0; i < n; i++)
    cin >> a[i];
  ll val[n];
  for (i = 0; i < n; i++)
    val[i] = 0;

  buildtree(val, 0, 0, n - 1);
  for (i = 1; i <= n; i++) {
    ll pos = rev[i];
    ll temp = query(1, pos + 1);
    ans = max(ans, temp + a[pos]);
    update(val, a[pos] + temp, pos + 1);
    val[pos] = a[pos] + temp;
    // for(j=0;j<n;j++)
    // 	cout<<val[j]<<" ";
    // cout<<endl;
  }

  cout << ans << endl;

  return 0;
}


Fixed submission:
/*░   ░▄▀▀▀▄░Prashik░░
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#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define M 1000000007
#define fastio                                                                 \
  ios_base::sync_with_stdio(false);                                            \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define endl "\n"
#define all(x) (x).begin(), (x).end()
#define tr(x, it) for (auto it = x.begin(); it != x.end(); ++it)
#define fpresent(x, c) ((c).find(x) != (c).end())    // set,map
#define present(c, x) (find(all(c), x) != (c).end()) // vector
#define pb push_back
#define mp make_pair
#define setv(ar, val) memset(ar, val, sizeof(ar));
#define error(args...)                                                         \
  {                                                                            \
    string _s = #args;                                                         \
    replace(_s.begin(), _s.end(), ',', ' ');                                   \
    stringstream _ss(_s);                                                      \
    istream_iterator<string> _it(_ss);                                         \
    err(_it, args);                                                            \
  }
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  err(++it, args...);
}

vector<ll> tree(4000000);

ll n;

void buildtree(ll a[], ll node, ll left, ll right) {
  if (left == right) {
    tree[node] = a[left];
  } else {
    ll mid = (left + right) / 2;
    buildtree(a, 2 * node + 1, left, mid);
    buildtree(a, 2 * node + 2, mid + 1, right);
    tree[node] =
        max(tree[2 * node + 1],
            tree[2 * node +
                 2]); // this tree is for the sum in the given range query ,
                      // this line can be modified according to the need for
                      // example, if we have to find the minimum in the given
                      // range we can accordingly change the line of command;
  }
}
void updateutil(
    ll a[], ll x, ll pos, ll left, ll right,
    ll node) // give the val to be updated and the pos where to update. pos
             // should be with respect to the original array.
{
  if (left == right) {
    a[pos] = x;
    tree[node] = x;
  } else {
    ll mid = (left + right) / 2;
    if (pos <= mid) {
      updateutil(a, x, pos, left, mid, 2 * node + 1);
    } else
      updateutil(a, x, pos, mid + 1, right, 2 * node + 2);
    tree[node] = max(tree[2 * node + 1],
                     tree[2 * node + 2]); // this line can be changed
                                          // accordingly for a different query
  }
}
void update(ll a[], ll x, ll pos) { updateutil(a, x, pos - 1, 0, n - 1, 0); }
void prlltree() {
  for (ll i = 0; i < 2 * n - 1; i++)
    cout << tree[i] << endl;
}
ll queryutil(ll left, ll right, ll l, ll r, ll node) {

  if (left == l && right == r) {
    return tree[node];
  } else {
    if (left <= right) {
      ll mid = (l + r) / 2;
      if (mid >= right) {
        return queryutil(left, right, l, mid, 2 * node + 1);
      }
      if (left > mid) {
        return queryutil(left, right, mid + 1, r, 2 * node + 2);
      }
      if (left <= mid && right > mid) {
        return max(queryutil(left, mid, l, mid, 2 * node + 1),
                   queryutil(mid + 1, right, mid + 1, r,
                             2 * node + 2)); // this line can be changed for
                                             // minimum or maximum query
      }
    } else
      return 0;
  }
}
ll query(ll left, ll right) {
  return queryutil(left - 1, right - 1, 0, n - 1, 0);
}

int main() {
  // freopen("input.in","r",stdin);
  // freopen("output.in","w",stdout);
  fastio;
  cin.tie(NULL);
  ll m, i, j, k, ans = 0;
  cin >> n;
  ll h[n], a[n], rev[n + 1];
  for (i = 0; i < n; i++) {
    cin >> h[i];
    rev[h[i]] = i;
  }
  for (i = 0; i < n; i++)
    cin >> a[i];
  ll val[n];
  for (i = 0; i < n; i++)
    val[i] = 0;

  buildtree(val, 0, 0, n - 1);
  for (i = 1; i <= n; i++) {
    ll pos = rev[i];
    ll temp = query(1, pos + 1);
    ans = max(ans, temp + a[pos]);
    update(val, a[pos] + temp, pos + 1);
    val[pos] = a[pos] + temp;
    // for(j=0;j<n;j++)
    // 	cout<<val[j]<<" ";
    // cout<<endl;
  }

  cout << ans << endl;

  return 0;
}