Language: C++

#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
 
typedef std::uint64_t u64;
typedef std::int64_t  i64;
typedef std::uint32_t u32;
typedef std::int32_t  i32;
 
using namespace std;
 
int main(int argc, const char* argv[]) {
  u64 x, y, z, num;
  cin >> x >> y >> z >> num;
  
  vector<u64> a(x, 0), b(y, 0), c(z, 0);
  for(u64 i = 0; i < x; ++i) cin >> a[i];
  for(u64 i = 0; i < y; ++i) cin >> b[i];
  for(u64 i = 0; i < z; ++i) cin >> c[i];
  
  sort(a.begin(), a.end(), greater<u64>());
  sort(b.begin(), b.end(), greater<u64>());
  sort(c.begin(), c.end(), greater<u64>());
  
  vector<u64> d(x + y, 0);
  
  for(u64 i = 0; i < x; ++i) {
    for(u64 j = 0; j < y; ++j) {
      d[i * y + j] = a[i] + b[j];
    }
  }
  
  sort(d.begin(), d.end(), greater<u64>());
  d.resize(min(num, x+y));
  vector<u64> e(d.size() + z, 0);
  
  for(u64 i = 0; i < d.size(); ++i) {
    for(u64 j = 0; j < z; ++j) {
      e[i*z+j] = d[i] + c[j];
    }
  }
  
  sort(e.begin(), e.end(), greater<u64>());
  
  for(u64 i = 0; i < min(k, e.size()); ++k) {
    cout << e[i] << endl;
  }        
  
  return 0;
}

Compiler output:
a.cc:11:14: error: 'uint64_t' in namespace 'std' does not name a type; did you mean 'wint_t'?
   11 | typedef std::uint64_t u64;
      |              ^~~~~~~~
      |              wint_t
a.cc:12:14: error: 'int64_t' in namespace 'std' does not name a type
   12 | typedef std::int64_t  i64;
      |              ^~~~~~~
a.cc:13:14: error: 'uint32_t' in namespace 'std' does not name a type; did you mean 'wint_t'?
   13 | typedef std::uint32_t u32;
      |              ^~~~~~~~
      |              wint_t
a.cc:14:14: error: 'int32_t' in namespace 'std' does not name a type
   14 | typedef std::int32_t  i32;
      |              ^~~~~~~
a.cc: In function 'int main(int, const char**)':
a.cc:19:3: error: 'u64' was not declared in this scope
   19 |   u64 x, y, z, num;
      |   ^~~
a.cc:20:10: error: 'x' was not declared in this scope
   20 |   cin >> x >> y >> z >> num;
      |          ^
a.cc:20:15: error: 'y' was not declared in this scope; did you mean 'yn'?
   20 |   cin >> x >> y >> z >> num;
      |               ^
      |               yn
a.cc:20:20: error: 'z' was not declared in this scope
   20 |   cin >> x >> y >> z >> num;
      |                    ^
a.cc:20:25: error: 'num' was not declared in this scope; did you mean 'enum'?
   20 |   cin >> x >> y >> z >> num;
      |                         ^~~
      |                         enum
a.cc:22:13: error: template argument 2 is invalid
   22 |   vector<u64> a(x, 0), b(y, 0), c(z, 0);
      |             ^
a.cc:22:21: error: expression list treated as compound expression in initializer [-fpermissive]
   22 |   vector<u64> a(x, 0), b(y, 0), c(z, 0);
      |                     ^
a.cc:22:30: error: expression list treated as compound expression in initializer [-fpermissive]
   22 |   vector<u64> a(x, 0), b(y, 0), c(z, 0);
      |                              ^
a.cc:22:39: error: expression list treated as compound expression in initializer [-fpermissive]
   22 |   vector<u64> a(x, 0), b(y, 0), c(z, 0);
      |                                       ^
a.cc:23:10: error: expected ';' before 'i'
   23 |   for(u64 i = 0; i < x; ++i) cin >> a[i];
      |          ^~
      |          ;
a.cc:23:18: error: 'i' was not declared in this scope
   23 |   for(u64 i = 0; i < x; ++i) cin >> a[i];
      |                  ^
a.cc:24:10: error: expected ';' before 'i'
   24 |   for(u64 i = 0; i < y; ++i) cin >> b[i];
      |          ^~
      |          ;
a.cc:24:18: error: 'i' was not declared in this scope
   24 |   for(u64 i = 0; i < y; ++i) cin >> b[i];
      |                  ^
a.cc:25:10: error: expected ';' before 'i'
   25 |   for(u64 i = 0; i < z; ++i) cin >> c[i];
      |          ^~
      |          ;
a.cc:25:18: error: 'i' was not declared in this scope
   25 |   for(u64 i = 0; i < z; ++i) cin >> c[i];
      |                  ^
a.cc:27:10: error: request for member 'begin' in 'a', which is of non-class type 'int'
   27 |   sort(a.begin(), a.end(), greater<u64>());
      |          ^~~~~
a.cc:27:21: error: request for member 'end' in 'a', which is of non-class type 'int'
   27 |   sort(a.begin(), a.end(), greater<u64>());
      |                     ^~~
a.cc:28:10: error: request for member 'begin' in 'b', which is of non-class type 'int'
   28 |   sort(b.begin(), b.end(), greater<u64>());
      |          ^~~~~
a.cc:28:21: error: request for member 'end' in 'b', which is of non-class type 'int'
   28 |   sort(b.begin(), b.end(), greater<u64>());
      |                     ^~~
a.cc:29:10: error: request for member 'begin' in 'c', which is of non-class type 'int'
   29 |   sort(c.begin(), c.end(), greater<u64>());
      |          ^~~~~
a.cc:29:21: error: request for member 'end' in 'c', which is of non-class type 'int'
   29 |   sort(c.begin(), c.end(), greater<u64>());
      |                     ^~~
a.cc:31:13: error: template argument 2 is invalid
   31 |   vector<u64> d(x + y, 0);
      |             ^
a.cc:31:25: error: expression list treated as compound expression in initializer [-fpermissive]
   31 |   vector<u64> d(x + y, 0);
      |                         ^
a.cc:33:10: error: expected ';' before 'i'
   33 |   for(u64 i = 0; i < x; ++i) {
      |          ^~
      |          ;
a.cc:33:18: error: 'i' was not declared in this scope
   33 |   for(u64 i = 0; i < x; ++i) {
      |                  ^
a.cc:34:12: error: expected ';' before 'j'
   34 |     for(u64 j = 0; j < y; ++j) {
      |            ^~
      |            ;
a.cc:34:20: error: 'j' was not declared in this scope
   34 |     for(u64 j = 0; j < y; ++j) {
      |                    ^
a.cc:39:10: error: request for member 'begin' in 'd', which is of non-class type 'int'
   39 |   sort(d.begin(), d.end(), greater<u64>());
      |          ^~~~~
a.cc:39:21: error: request for member 'end' in 'd', which is of non-class type 'int'
   39 |   sort(d.begin(), d.end(), greater<u64>());
      |                     ^~~
a.cc:40:5: error: request for member 'resize' in 'd', which is of non-class type 'int'
   40 |   d.resize(min(num, x+y));
      |     ^~~~~~
a.cc:41:13: error: template argument 2 is invalid
   41 |   vector<u64> e(d.size() + z, 0);
      |             ^
a.cc:41:19: error: request for member 'size' in 'd', which is of non-class type 'int'
   41 |   vector<u64> e(d.size() + z, 0);
      |                   ^~~~
a.cc:41:32: error: expression list treated as compound expression in initializer [-fpermissive]
   41 |   vector<u64> e(d.size() + z, 0);
      |                                ^
a.cc:43:10: error: expected ';' before 'i'
   43 |   for(u64 i = 0; i < d.size(); ++i) {
      |          ^~
      |          ;
a.cc:43:18: error: 'i' was not declared in this scope
   43 |   for(u64 i = 0; i < d.size(); ++i) {
      |                  ^
a.cc:43:24: error: request for member 'size' in 'd', which is of non-class type 'int'
   43 |   for(u64 i = 0; i < d.size(); ++i) {
      |                        ^~~~
a.cc:44:12: error: expected ';' before 'j'
   44 |     for(u64 j = 0; j < z; ++j) {
      |            ^~
      |            ;
a.cc:44:20: error: 'j' was not declared in this scope
   44 |     for(u64 j = 0; j < z; ++j) {
      |                    ^
a.cc:49:10: error: request for member 'begin' in 'e', which is of non-class type 'int'
   49 |   sort(e.begin(), e.end(), greater<u64>());
      |          ^~~~~
a.cc:49:21: error: request for member 'end' in 'e', which is of non-class type 'int'
   49 |   sort(e.begin(), e.end(), greater<u64>());
      |                     ^~~
a.cc:51:10: error: expected ';' before 'i'
   51 |   for(u64 i = 0; i < min(k, e.size()); ++k) {
      |          ^~
      |          ;
a.cc:51:18: error: 'i' was not declared in this scope
   51 |   for(u64 i = 0; i < min(k, e.size()); ++k) {
      |                  ^
a.cc:51:26: error: 'k' was not declared in this scope
   51 |   for(u64 i = 0; i < min(k, e.size()); ++k) {
      |                          ^
a.cc:51:31: error: request for member 'size' in 'e', which is of non-class type 'int'
   51 |   for(u64 i = 0; i < min(k, e.size()); ++k) {
      |                               ^~~~