Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  int N, A, B, C;
  cin >> N >> A >> B >> C;
  vector<string> S(N);
  for (int i = 0; i < N; i++) cin >> S.at(i);
  
  if (A + B + C == 0) {
    cout << "No" << endl;
  }
  
  else if (A + B + C == 1) {
    string ans = "";
    for (int i = 0; i < N; i++) {
      if (S.at(i) == "AB") {
        if (A == 1) {
          ans += 'A';
          A--;
          B++;
        }
        else if (B == 1) {
          ans += 'B';
          B--;
          A++;
        }
        else {
          ans = "No";
          break;
        }
      }
      else if (S.at(i) == "AC") {
        if (A == 1) {
          ans += 'A';
          A--;
          C++;
        }
        else if (C == 1) {
          ans += 'C';
          C--;
          A++;
        }
        else {
          ans = "No";
          break;
        }
      }
      else {
        if (B == 1) {
          ans += 'B';
          B--;
          C++;
        }
        else if (C == 1) {
          ans += 'C';
          C--;
          B++;
        }
        else {
          ans = "No";
          break;
        }
      }
    }
    if (ans == "No") cout << ans << endl;
    else {
      for (int i = 0; i < ans.size(); i++) {
        cout << ans.at(i) << endl;
      }
    }
  }
  
  else {
    string ans = "";
    for (int i = 0; i < N; i++) {
      if (S.at(i) == "AB") {
        if (A == 0 && B == 0) {
          ans = "No";
          break;
        }
        else if (A > B) {
          ans += 'A';
          A--;
          B++;
        }
        else if (B > A) {
          ans += 'B';
          B--;
          A++;
        }
        else {
          if (i < N - 1 && S.at(i + 1) == "AC") {
            ans += 'B';
            B--;
            A++;
          }
          else {
            ans += 'A';
            A--;
            B++;
          }
        }
      }
      else if (S.at(i) == "AC") {
        if (A == 0 && C == 0) {
          ans = "No";
          break;
        }
        else if (A > C) {
          ans += 'A';
          A--;
          C++;
        }
        else if (C > A) {
          ans += 'C';
          C--;
          A++;
        }
        else {
          if (i < N - 1 && S.at(i + 1) == "AB") {
            ans += 'C';
            C--;
            A++;
          }
          else {
            ans += 'A';
            A--;
            C++;
          }
        }
      }
      else {
        if (B == 0 && C == 0) {
          ans = "No";
          break;
        }
        else if (B > C) {
          ans += 'B';
          B--;
          C++;
        }
        else if (C > B) {
          ans += 'C';
          C--;
          B++;
        }
        else {
          if (i < N - 1 && S.at(i + 1) == 'AC') {
            ans += 'B';
            B--;
            C++;
          }
          else {
            ans += 'C';
            C--;
            B++;
          }
        }
      }
    }
    if (ans == "No") cout << ans << endl;
    else {
      for (int i = 0; i < S.size(); i++) {
        cout << S.at(i) << endl;
      }
    }
  }
}


Compiler output:
a.cc:149:43: warning: multi-character character constant [-Wmultichar]
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
a.cc: In function 'int main()':
a.cc:149:40: error: no match for 'operator==' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} and 'int')
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                            ~~~~~~~~~~~ ^~ ~~~~
      |                                |          |
      |                                |          int
      |                                __gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type {aka std::__cxx11::basic_string<char>}
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:1103:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1103 |     operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1103:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:1199:5: 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>&)'
 1199 |     operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1199:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:1274:5: 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>&)'
 1274 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1274:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:1366:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1366 |     operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1366:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:1441:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1441 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1441:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:1534:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1534 |     operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1534:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:1613:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1613 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1613:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/regex.h:2186:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator==(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2186 |     operator==(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2186:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
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:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::pair<_T1, _T2>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:149:43: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
  149 |           if (i < N - 1 && S.at(i + 1) == 'AC') {
      |                                           ^~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument ded