Problem p02537 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define dd double
#define endl "\\n"
#define pb push_back
#define all(v) v.begin(), v.end()
#define mp make_pair
#define fi first
#define se second
#define vll vector<ll>
#define pll pair<ll, ll>
#define fo(i, n) for (int i = 0; i < n; i++)
#define fo1(i, n) for (int i = 1; i <= n; i++)
ll mod = 1000000007;
ll n, k, t, m, q, flag = 0;
ll power(ll a, ll b) {
  ll res = 1;
  a %= mod;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1)
      res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// #define ordered_set tree<int, null_type,less<int>,
// rb_tree_tag,tree_order_statistics_node_update> ordered_set s ;
// s.order_of_key(a) -- no. of elements strictly less than a s.find_by_order(i)
// -- itertor to ith element (0 indexed)
ll min(ll a, ll b) {
  if (a > b)
    return b;
  else
    return a;
}
ll max(ll a, ll b) {
  if (a > b)
    return a;
  else
    return b;
}
ll gcd(ll a, ll b) {
  if (b > a)
    return gcd(b, a);
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll tree[1200001];
ll a[300001];
void update(ll mini, ll maxi, ll treeindex, ll index, ll val) {
  if (mini == maxi) {
    tree[treeindex] = val;
    return;
  }
  ll mid = (mini + maxi) / 2;
  if (mid >= index) {
    update(mini, mid, 2 * treeindex, index, val);
  } else
    update(mid + 1, maxi, 2 * treeindex + 1, index, val);
  tree[treeindex] = max(tree[treeindex * 2], tree[2 * treeindex + 1]);
}

ll maxval(ll mini, ll maxi, ll l, ll r, ll index) {
  if (l > r)
    return 0;
  if (l == mini && r == maxi) {
    return tree[index];
  }
  ll mid = (mini + maxi) / 2;
  return max(maxval(mini, mid, l, min(r, mid), 2 * index),
             maxval(mid + 1, maxi, max(l, mid + 1), r, 2 * index + 1));
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifdef NOOBxCODER
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#else
#define NOOBxCODER 0
#endif
  // cin>>t;
  t = 1;
  while (t--) {
    cin >> n;
    cin >> k;
    fo(i, n) cin >> a[i];
    // fo(i,300001)node[i]=0;
    fo(i, 1200001) tree[i] = 0;
    ll ans;
    fo(i, n) {
      ll val =
          maxval(0, 300000, max(0, a[i] - k), min(300000, a[i] + k), 1) + 1;
      update(0, 300000, 1, a[i], val);
    }
    cout << tree[1];
  }
  cerr << "Time : " << 1000 * ((double)clock()) / (double)CLOCKS_PER_SEC
       << "ms\\n";
  return 0;
}


Error: WA

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define dd double
#define endl "\\n"
#define pb push_back
#define all(v) v.begin(), v.end()
#define mp make_pair
#define fi first
#define se second
#define vll vector<ll>
#define pll pair<ll, ll>
#define fo(i, n) for (int i = 0; i < n; i++)
#define fo1(i, n) for (int i = 1; i <= n; i++)
ll mod = 1000000007;
ll n, k, t, m, q, flag = 0;
ll power(ll a, ll b) {
  ll res = 1;
  a %= mod;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1)
      res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// #define ordered_set tree<int, null_type,less<int>,
// rb_tree_tag,tree_order_statistics_node_update> ordered_set s ;
// s.order_of_key(a) -- no. of elements strictly less than a s.find_by_order(i)
// -- itertor to ith element (0 indexed)
ll min(ll a, ll b) {
  if (a > b)
    return b;
  else
    return a;
}
ll max(ll a, ll b) {
  if (a > b)
    return a;
  else
    return b;
}
ll gcd(ll a, ll b) {
  if (b > a)
    return gcd(b, a);
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll tree[900001];
ll a[300000];
void update(ll mini, ll maxi, ll treeindex, ll index, ll val) {
  if (mini == maxi) {
    tree[treeindex] = val;
    return;
  }
  ll mid = (mini + maxi) / 2;
  if (mid >= index) {
    update(mini, mid, 2 * treeindex, index, val);
  } else
    update(mid + 1, maxi, 2 * treeindex + 1, index, val);
  tree[treeindex] = max(tree[treeindex * 2], tree[2 * treeindex + 1]);
}

ll maxval(ll mini, ll maxi, ll l, ll r, ll index) {
  if (l > r)
    return 0;
  if (l == mini && r == maxi) {
    return tree[index];
  }
  ll mid = (mini + maxi) / 2;
  return max(maxval(mini, mid, l, min(r, mid), 2 * index),
             maxval(mid + 1, maxi, max(l, mid + 1), r, 2 * index + 1));
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifdef NOOBxCODER
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#else
#define NOOBxCODER 0
#endif
  // cin>>t;
  t = 1;
  while (t--) {
    cin >> n;
    cin >> k;
    fo(i, n) cin >> a[i];
    // fo(i,300001)node[i]=0;
    fo(i, 900001) tree[i] = 0;
    ll ans;
    fo(i, n) {
      ll val =
          maxval(0, 300000, max(0, a[i] - k), min(300000, a[i] + k), 1) + 1;
      update(0, 300000, 1, a[i], val);
    }
    cout << tree[1];
  }
  cerr << "Time : " << 1000 * ((double)clock()) / (double)CLOCKS_PER_SEC
       << "ms\\n";
  return 0;
}