Problem p02598 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<ll, ll>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, k;
  cin, n, k;
  vector<ll> a(n);
  REP(i, 0, n) { cin, a[i]; }
  ll l = 0, r = 1000000010;
  ll ans = r;
  while (l <= r) {
    ll mid = (l + r) / 2;
    ll cnt = 0;
    auto vv = a;
    REP(i, 0, n) {
      vv[i] -= mid;
      chmax(vv[i], 0LL);
    }
    REP(i, 0, n) { cnt += (vv[i] + mid - 1) / mid; }
    if (k >= cnt) {
      r = mid - 1;
      chmin(ans, mid);
    } else {
      l = mid + 1;
    }
  }
  print(ans);

  return 0;
}


Fixed submission:
#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<ll, ll>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, k;
  cin, n, k;
  vector<ll> a(n);
  REP(i, 0, n) { cin, a[i]; }
  ll l = 1, r = 1000000010;
  ll ans = r;
  while (l <= r) {
    ll mid = (l + r) / 2;
    ll cnt = 0;
    auto vv = a;
    REP(i, 0, n) {
      vv[i] -= mid;
      chmax(vv[i], 0LL);
    }
    REP(i, 0, n) { cnt += (vv[i] + mid - 1) / mid; }
    if (k >= cnt) {
      r = mid - 1;
      chmin(ans, mid);
    } else {
      l = mid + 1;
    }
  }
  print(ans);

  return 0;
}