Forth

input/code.cpp: In function 'int main()':
input/code.cpp:39:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |   for (int i = 0; i < ops.size(); i++) {
      |                   ~~^~~~~~~~~~~~
input/code.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |     cout << ops[i] << (i == ops.size()-1 ? "" : " ");
      |                        ~~^~~~~~~~~~~~~~~

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
 
#ifdef LOCAL
#include "debug.hpp"
#else
#define debug(...) 0xffff
#endif
 
 
 
int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);
  int x; cin>>x;
 
  // [1]
  // DUP [1, 1]
  // DUP [1, 1, 1]
  // 
 
  if (x == 1) return cout << "2\nDUP DROP", 0;
 
  // keep adding till it's x
  vector<string> ops = {"DUP"};
 
  int cur = 1;
  while (cur < x) {
    ops.push_back("DUP");
    ops.push_back("ROT");
    ops.push_back("+");
    ops.push_back("SWAP");
    cur++;
  }
 
  ops.push_back("DROP");
 
  cout << ops.size() <<"\n";
  for (int i = 0; i < ops.size(); i++) {
    cout << ops[i] << (i == ops.size()-1 ? "" : " ");
  }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED