Problem p02598 (C++)

Buggy submission (status: Time Limit Exceeded):
#pragma region header
#include <bits/stdc++.h>
#define int long long
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
#define mp make_pair
#define mt make_tuple
#define rep1(i, n) for (decltype(+n) i = 0; i < (n); i++)
#define rrep1(i, n) for (auto i = n - 1; i > static_cast<decltype(i)>(-1); i--)
#define rep2(i, a, b) for (auto i = (a); i < (b); i++)
#define rrep2(i, a, b) for (auto i = b - 1; i >= a; i--)
#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define rep(...) GET_MACRO(__VA_ARGS__, rep2, rep1)(__VA_ARGS__)
#define rrep(...) GET_MACRO(__VA_ARGS__, rrep2, rrep1)(__VA_ARGS__)
#define each(i, a) for (auto &&i : (a))
using namespace std;

using ld = long double;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using vvs = vector<vs>;
using vd = vector<ld>;
using vvd = vector<vd>;
using vb = vector<bool>;
using vvb = vector<vb>;
using pii = pair<int, int>;
using vp = vector<pii>;
using vvp = vector<vp>;
using mii = map<int, int>;
using vm = vector<mii>;
using vvm = vector<vm>;
template <class T, class U> using umap = unordered_map<T, U>;
using umii = umap<int, int>;
using seti = set<int>;
template <class T> using uset = unordered_set<T>;
using useti = uset<int>;
template <class T> using less_queue = priority_queue<T>;
template <class T>
using greater_queue = priority_queue<T, vector<T>, greater<T>>;

constexpr int INF = 1e18;

template <class T> void SORT(T &a) { stable_sort(all(a)); }
template <class T> void RSORT(T &a) { stable_sort(rall(a)); }
template <class T> void rev(T &a) { reverse(rall(a)); }
template <class T> void uniq(T &a) { a.erase(unique(all(a)), end(a)); }
template <class T> auto min_of(T a) { return *min_element(all(a)); }
template <class T> auto max_of(T a) { return *max_element(all(a)); }
template <class T> int sum_of(T a) { return accumulate(all(a), 0ll); }
template <class T, class U> auto sum_of(T a, U init) {
  return accumulate(all(a), init);
}
template <class T, class U> int count_of(T a, U i) { return count(all(a), i); }
template <class T, class U> bool has(T a, U i) {
  return find(all(a), i) != end(a);
}
template <class T> int sz(T a) { return a.size(); };

template <class T> void COUT(T x) { cout << x << endl; }
template <class T, class U> void COUT(T x, U y) {
  cout << x << ' ' << y << endl;
}
template <class T, class U, class V> void COUT(T x, U y, V z) {
  cout << x << ' ' << y << ' ' << z << endl;
}
template <class T> void CSP(T x) { cout << x << ' '; }
template <class T> void CVEC(T v) {
  int c = v.size() - 1;
  for (size_t i = 0; i < c; i++)
    cout << v[i] << ' ';
  if (c > -1)
    cout << v[c];
  cout << endl;
}

template <class T> bool amin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> bool amax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

constexpr int lshift(int x) noexcept { return 1ll << x; }
constexpr int popcount(unsigned int x) noexcept {
  return __builtin_popcountll(x);
}
constexpr int least1(unsigned int x) noexcept { return __builtin_ffsll(x); }
constexpr int ceil_div(int x, int y) noexcept { return (x - 1) / y + 1; }

#pragma endregion header

// no MOD

void solve(int n, int k, vi a) {
  RSORT(a);
  int l = 0, r = a[0];
  while (r - l > 1) {
    int m = (l + r) / 2;
    int cnt = k;
    bool ok = true;
    rep(i, n) {
      bool cut = false;
      rep(d, cnt + 1) {
        if (ceil_div(a[i], d + 1) <= m) {
          cnt -= d;
          cut = true;
          break;
        }
      }
      if (!cut) {
        ok = false;
        break;
      }
    }
    (ok ? r : l) = m;
  }
  COUT(r);
}

#pragma region main
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(15);

  int n;
  cin >> n;
  int k;
  cin >> k;
  vi a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  solve(n, k, move(a));
}
#pragma endregion main


Fixed submission:
#pragma region header
#include <bits/stdc++.h>
#define int long long
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
#define mp make_pair
#define mt make_tuple
#define rep1(i, n) for (decltype(+n) i = 0; i < (n); i++)
#define rrep1(i, n) for (auto i = n - 1; i > static_cast<decltype(i)>(-1); i--)
#define rep2(i, a, b) for (auto i = (a); i < (b); i++)
#define rrep2(i, a, b) for (auto i = b - 1; i >= a; i--)
#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define rep(...) GET_MACRO(__VA_ARGS__, rep2, rep1)(__VA_ARGS__)
#define rrep(...) GET_MACRO(__VA_ARGS__, rrep2, rrep1)(__VA_ARGS__)
#define each(i, a) for (auto &&i : (a))
using namespace std;

using ld = long double;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using vvs = vector<vs>;
using vd = vector<ld>;
using vvd = vector<vd>;
using vb = vector<bool>;
using vvb = vector<vb>;
using pii = pair<int, int>;
using vp = vector<pii>;
using vvp = vector<vp>;
using mii = map<int, int>;
using vm = vector<mii>;
using vvm = vector<vm>;
template <class T, class U> using umap = unordered_map<T, U>;
using umii = umap<int, int>;
using seti = set<int>;
template <class T> using uset = unordered_set<T>;
using useti = uset<int>;
template <class T> using less_queue = priority_queue<T>;
template <class T>
using greater_queue = priority_queue<T, vector<T>, greater<T>>;

constexpr int INF = 1e18;

template <class T> void SORT(T &a) { stable_sort(all(a)); }
template <class T> void RSORT(T &a) { stable_sort(rall(a)); }
template <class T> void rev(T &a) { reverse(rall(a)); }
template <class T> void uniq(T &a) { a.erase(unique(all(a)), end(a)); }
template <class T> auto min_of(T a) { return *min_element(all(a)); }
template <class T> auto max_of(T a) { return *max_element(all(a)); }
template <class T> int sum_of(T a) { return accumulate(all(a), 0ll); }
template <class T, class U> auto sum_of(T a, U init) {
  return accumulate(all(a), init);
}
template <class T, class U> int count_of(T a, U i) { return count(all(a), i); }
template <class T, class U> bool has(T a, U i) {
  return find(all(a), i) != end(a);
}
template <class T> int sz(T a) { return a.size(); };

template <class T> void COUT(T x) { cout << x << endl; }
template <class T, class U> void COUT(T x, U y) {
  cout << x << ' ' << y << endl;
}
template <class T, class U, class V> void COUT(T x, U y, V z) {
  cout << x << ' ' << y << ' ' << z << endl;
}
template <class T> void CSP(T x) { cout << x << ' '; }
template <class T> void CVEC(T v) {
  int c = v.size() - 1;
  for (size_t i = 0; i < c; i++)
    cout << v[i] << ' ';
  if (c > -1)
    cout << v[c];
  cout << endl;
}

template <class T> bool amin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> bool amax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

constexpr int lshift(int x) noexcept { return 1ll << x; }
constexpr int popcount(unsigned int x) noexcept {
  return __builtin_popcountll(x);
}
constexpr int least1(unsigned int x) noexcept { return __builtin_ffsll(x); }
constexpr int ceil_div(int x, int y) noexcept { return (x - 1) / y + 1; }

#pragma endregion header

// no MOD

void solve(int n, int k, vi a) {
  RSORT(a);
  int l = 0, r = a[0];
  while (r - l > 1) {
    int m = (l + r) / 2;
    int cnt = k;
    bool ok = true;
    rep(i, n) {
      cnt -= ceil_div(a[i], m) - 1;
      if (cnt < 0) {
        ok = false;
        break;
      }
    }
    (ok ? r : l) = m;
  }
  COUT(r);
}

#pragma region main
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(15);

  int n;
  cin >> n;
  int k;
  cin >> k;
  vi a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  solve(n, k, move(a));
}
#pragma endregion main