Problem p02598 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define INF (1 << 29)
#define LINF (1LL << 60)
#define EPS (1e-10)
#define PI 3.1415926535897932384626433832795028
#define all(a) (a).begin(), (a).end()
#define sz(x) (int)x.size()
#define max_heap priority_queue<int>
#define min_heap priority_queue<int, vector<int>, greater<int>>
using ll = long long;
#define int long long
#define endl "\n"
#define vi vector<int>
#define pb push_back
#define inp_arr(a, n)                                                          \
  for (ll i = 0; i < n; i++)                                                   \
    cin >> a[i];
#define out_arr(a)                                                             \
  for (ll i = 0; i < a.size(); i++)                                            \
    cout << a[i] << " ";
#define deb(n) cerr << #n << " = " << n << "\n";
int gcd(int a, int b) {
  if (a == 0)
    return b;
  return gcd(b % a, a);
}
ll mypower(ll x, ll n, ll c) {
  if (n == 0)
    return 1;
  ll temp = mypower(x, n / 2, c) % c;
  if (n % 2)
    return (n < 0) ? (1 / x) * temp * temp % c : ((x * temp) % c) * temp % c;
  else
    return temp * temp % c;
}
bool codejam = 0;

bool check(ll mid, vector<int> a, ll k) {
  ll ans = 0;
  for (int i = 0; i < a.size(); i++) {
    if (a[i] > mid) {
      ans += a[i] / mid;
    }
  }
  return ans <= k;
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif

  ll n;
  ll k;
  cin >> n >> k;
  vector<int> a(n);
  inp_arr(a, n);
  ll low = 0;
  ll high = *max_element(all(a));
  while (low < high) {
    ll mid = low + (high - low) / 2;
    if (check(mid, a, k))
      high = mid;
    else
      low = mid + 1;
  }
  cout << low << endl;
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define INF (1 << 29)
#define LINF (1LL << 60)
#define EPS (1e-10)
#define PI 3.1415926535897932384626433832795028
#define all(a) (a).begin(), (a).end()
#define sz(x) (int)x.size()
#define max_heap priority_queue<int>
#define min_heap priority_queue<int, vector<int>, greater<int>>
using ll = long long;
#define int long long
#define endl "\n"
#define vi vector<int>
#define pb push_back
#define inp_arr(a, n)                                                          \
  for (ll i = 0; i < n; i++)                                                   \
    cin >> a[i];
#define out_arr(a)                                                             \
  for (ll i = 0; i < a.size(); i++)                                            \
    cout << a[i] << " ";
#define deb(n) cerr << #n << " = " << n << "\n";
int gcd(int a, int b) {
  if (a == 0)
    return b;
  return gcd(b % a, a);
}
ll mypower(ll x, ll n, ll c) {
  if (n == 0)
    return 1;
  ll temp = mypower(x, n / 2, c) % c;
  if (n % 2)
    return (n < 0) ? (1 / x) * temp * temp % c : ((x * temp) % c) * temp % c;
  else
    return temp * temp % c;
}
bool codejam = 0;

bool check(ll mid, vector<int> a, ll k) {
  ll ans = 0;
  for (int i = 0; i < a.size(); i++) {
    if (a[i] > mid) {
      ans += a[i] / mid;
    }
  }
  return ans <= k;
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif

  ll n;
  ll k;
  cin >> n >> k;
  vector<int> a(n);
  inp_arr(a, n);
  ll low = 0;
  ll high = *max_element(all(a));
  while (low < high) {
    ll mid = low + (high - low) / 2;
    if (mid and check(mid, a, k))
      high = mid;
    else
      low = mid + 1;
  }
  cout << low << endl;
  return 0;
}