Language: C++

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

#define rep(i, n) for (int i = 0; i < (int) (n); i++)
#define all(v) v.begin(), v.end()

struct node {
  int x, y, z;
  ll v;
  node(int a, int b, int c, ll d) : x(a), y(b), z(c), v(d) {}
  bool operator<(const node b) const {
    return v < b.v;
  }
  bool operator>(const node b) const {
    return b < (*this);
  }
};

vector<ll> a, b, c;

node calc(int x, int y, int z)
{
  if (x < a.size() && y < b.size() && z < c.size()) {
    node n(x, y, z, a[x] + b[y] + c[z]);
    return n;
  }
  node n(x, y, z, 0);
  return n;
}

int main()
{
  int x, y, z, k;
  cin >> x >> y >> z >> k;
  a.resize(x);
  b.resize(y);
  c.resize(z);
  rep(i, x) cin >> a[i];
  rep(i, y) cin >> b[i];
  rep(i, z) cin >> c[i];
  sort(all(a), greater<ll>());
  sort(all(b), greater<ll>());
  sort(all(c), greater<ll>());
  priority_queue<node> q;
  q.push(calc(0, 0, 0));
  unordered_set<node> s;
  s.insert(calc(0, 0, 0));
  while (1) {
    if (k == 0) break;
    auto a = q.top();
    q.pop();
    cout << a.v << endl;
    node t = calc(a.x+1, a.y, a.z);
    if (s.count(t) == 0) {
      q.push(t);
      s.insert(t);
    }
    t = calc(a.x, a.y+1, a.z);
    if (s.count(t) == 0) {
      q.push(t);
      s.insert(t);
    }
    t = calc(a.x, a.y, a.z+1);
    if (s.count(t) == 0) {
      q.push(t);
      s.insert(t);
    }    
    k--;
  }
}



Compiler output:
a.cc: In function 'int main()':
a.cc:49:23: error: use of deleted function 'std::unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set() [with _Value = node; _Hash = std::hash<node>; _Pred = std::equal_to<node>; _Alloc = std::allocator<node>]'
   49 |   unordered_set<node> s;
      |                       ^
In file included from /usr/include/c++/14/unordered_set:41,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:189,
                 from a.cc:1:
/usr/include/c++/14/bits/unordered_set.h:142:7: note: 'std::unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set() [with _Value = node; _Hash = std::hash<node>; _Pred = std::equal_to<node>; _Alloc = std::allocator<node>]' is implicitly deleted because the default definition would be ill-formed:
  142 |       unordered_set() = default;
      |       ^~~~~~~~~~~~~
/usr/include/c++/14/bits/unordered_set.h: At global scope:
/usr/include/c++/14/bits/unordered_set.h:142:7: error: use of deleted function 'std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = node; _Value = node; _Alloc = std::allocator<node>; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<node>; _Hash = std::hash<node>; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]'
In file included from /usr/include/c++/14/bits/unordered_map.h:33,
                 from /usr/include/c++/14/unordered_map:41,
                 from /usr/include/c++/14/functional:63,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53:
/usr/include/c++/14/bits/hashtable.h:539:7: note: 'std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = node; _Value = node; _Alloc = std::allocator<node>; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<node>; _Hash = std::hash<node>; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]' is implicitly deleted because the default definition would be ill-formed:
  539 |       _Hashtable() = default;
      |       ^~~~~~~~~~
/usr/include/c++/14/bits/hashtable.h:539:7: error: use of deleted function 'std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = node; _Value = node; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<node>; _Hash = std::hash<node>; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, true, true>]'
In file included from /usr/include/c++/14/bits/hashtable.h:35:
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: note: 'std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = node; _Value = node; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<node>; _Hash = std::hash<node>; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, true, true>]' is implicitly deleted because the default definition would be ill-formed:
 1731 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: error: use of deleted function 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = node; _Value = node; _ExtractKey = std::__detail::_Identity; _Hash = std::hash<node>; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; bool __cache_hash_code = true]'
/usr/include/c++/14/bits/hashtable_policy.h: In instantiation of 'std::__detail::_Hashtable_ebo_helper<_Nm, _Tp, true>::_Hashtable_ebo_helper() [with int _Nm = 1; _Tp = std::hash<node>]':
/usr/include/c++/14/bits/hashtable_policy.h:1328:7:   required from here
 1328 |       _Hash_code_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1245:49: error: use of deleted function 'std::hash<node>::hash()'
 1245 |       _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
      |                                                 ^~~~~
In file included from /usr/include/c++/14/string_view:50,
                 from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<node>::hash()' is implicitly deleted because the default definition would be ill-formed:
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:102:12: error: no matching function for call to 'std::__hash_enum<node, false>::__hash_enum()'
/usr/include/c++/14/bits/functional_hash.h:83:7: note: candidate: 'std::__hash_enum<_Tp, <anonymous> >::__hash_enum(std::__hash_enum<_Tp, <anonymous> >&&) [with _Tp = node; bool <anonymous> = false]'
   83 |       __hash_enum(__hash_enum&&);
      |       ^~~~~~~~~~~
/usr/include/c++/14/bits/functional_hash.h:83:7: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/functional_hash.h:102:12: error: 'std::__hash_enum<_Tp, <anonymous> >::~__hash_enum() [with _Tp = node; bool <anonymous> = false]' is private within this context
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:84:7: note: declared private here
   84 |       ~__hash_enum();
      |       ^
/usr/include/c++/14/bits/hashtable_policy.h:1245:49: note: use '-fdiagnostics-all-candidates' to display considered candidates
 1245 |       _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
      |                                                 ^~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1328:7: note: 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = node; _Value = node; _ExtractKey = std::__detail::_Identity; _Hash = std::hash<node>; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; bool __cache_hash_code = true]' is implicitly deleted because the default definition would be ill-formed:
 1328 |       _Hash_code_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1328:7: error: use of deleted function 'std::__detail::_Hashtable_ebo_helper<1, std::hash<node>, true>::~_Hashtable_ebo_helper()'
/usr/include/c++/14/bits/hashtable_policy.h:1242:12: note: 'std::__detail::_Hashtable_ebo_helper<1, std::hash<node>, true>::~_Hashtable_ebo_helper()' is implicitly deleted because the default definition would be ill-formed:
 1242 |     struct _Hashtable_ebo_helper<_Nm, _Tp, true>
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1242:12: error: use of deleted function 'std::hash<node>::~hash()'
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<node>::~hash()' is implicitly deleted because the default definition would be ill-formed:
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:102:12: error: 'std::__hash_enum<_Tp, <anonymous> >::~__hash_enum() [with _Tp = node; bool <anonymous> = false]' is private within this context
/usr/include/c++/14/bits/functional_hash.h:84:7: note: declared private here
   84 |       ~__hash_enum();
      |       ^
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: note: use '-fdiagnostics-all-candidates' to display considered candidates
 1731 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: error: use of deleted function 'std::__detail::_Hash_code_base<node, node, std::__detail::_Identity, std::hash<node>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>::~_Hash_code_base()'
/usr/include/c++/14/bits/hashtable_policy.h:1306:12: note: 'std::__detail::_Hash_code_base<node, node, std::__detail::_Identity, std::hash<node>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>::~_Hash_code_base()' is implicitly deleted because the default definition would be ill-formed:
 1306 |     struct _Hash_code_base
      |            ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1306:12: error: use of deleted function 'std::__detail::_Hashtable_ebo_helper<1, std::hash<node>, true>::~_Hashtable_ebo_helper()'
/usr/include/c++/14/bits/hashtable.h:539:7: note: use '-fdiagnostics-all-candidates' to display considered candidates
  539 |       _Hashtable() = default;
      |       ^~~~~~~~~~
/usr/include/c++/14/bits/hashtable.h:539:7: error: use of deleted function 'std::__detail::_Hashtable_base<node, node, std::__detail::_Identity, std::equal_to<node>, std::hash<node>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Hashtable_traits<true, true, true> >::~_Hashtable_base()'
/usr/include/c++/14/bits/hashtable_policy.h:1688:12: note: 'std::__detail::_Hashtable_base<node, node, std::__detail::_Identity, std::equal_to<node>, std::hash<node>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Hashtable_traits<true, true, true> >::~_Hashtable_base()' is implicitly deleted because the default definition would be ill-formed:
 1688 |     struct _Hashtable_base
      |            ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1688:12: error: use of deleted function 'std::__detail::_Hash_code_base<node, node, std::__detail::_Identity, std::hash<node>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_ha