Language: C++

#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ALL(A) A.begin(),A.end()
#define RALL(A) A.rbegin(),A.rend()
typedef long long ll;
typedef pair<ll,ll> P;
const ll mod=1000000007;
const ll LINF=1LL<<60;
const int INF=1<<30;

int main(){
	int n;cin>>n;
	vector<vector<pair<string,int>>> v(12);
	v[1].pb(mp("a",0));
	for(int i = 2; i <= 10; i++) {
		for(int j = 0; j < v[i - 1].size(); j++) {
			for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
				v[i].pb(mp(v[i - 1][j].fs + (char)('a' + k),max(v[i - 1][j].sc,k)));
			}
		}
	}
	for(int i = 0; i < v[n].size(); i++) {
		cout << v[n][i].fs << endl;
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:57: error: expected ')' before numeric constant
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                             ~           ^~~~~
      |                                                         )
a.cc:22:42: error: no match for 'operator<=' (operand types are 'int' and '__gnu_cxx::__alloc_traits<std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >, std::pair<std::__cxx11::basic_string<char>, int> >::value_type' {aka 'std::pair<std::__cxx11::basic_string<char>, int>'})
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1154:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator<=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1154 |     operator<=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1154:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/regex.h:1260:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator<=(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1260 |     operator<=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1260:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/regex.h:1353:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator<=(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1353 |     operator<=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1353:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/regex.h:1427:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator<=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1427 |     operator<=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1427:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >, std::pair<std::__cxx11::basic_string<char>, int> >::value_type' {aka 'std::pair<std::__cxx11::basic_string<char>, int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/regex.h:1521:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator<=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1521 |     operator<=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1521:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/regex.h:1599:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator<=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1599 |     operator<=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1599:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >, std::pair<std::__cxx11::basic_string<char>, int> >::value_type' {aka 'std::pair<std::__cxx11::basic_string<char>, int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/regex.h:1699:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator<=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1699 |     operator<=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1699:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1064:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator<=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1064 |     operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1064:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::pair<_T1, _T2>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:469:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  469 |     operator<=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:469:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/stl_iterator.h:513:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  513 |     operator<=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:513:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/stl_iterator.h:1704:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1704 |     operator<=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1704:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/bits/stl_iterator.h:1767:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1767 |     operator<=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1767:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
In file included 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/string_view:717:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  717 |     operator<=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:717:5: note:   template argument deduction/substitution failed:
a.cc:22:66: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   22 |                         for(int k = 0; k <= (v[i - 1][j]10.sc + 1); k++) {
      |                                                                  ^
/usr/include/c++/14/string_view:724:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<=(basic_string_view<_CharT, _Traits>, __type_ident