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);
  
  bool ans = true;
  int ta = a, tb = b, tc = c;
  for(int i = 0; i < n; ++i){
    char x = s.at(i).at(0), y = s.at(i).at(1);
    if(i < n-1) char nx = s.at(i+1).at(0), ny = s.at(i+1).at(1);
    if(x != 'A' && y != 'A'){
      if(tb == tc && i < n-1){
        if(nx == 'B' || ny == 'B') tb++, tc--;
        else tb--, tc++;
      }
      else if(tb < tc) tb++, tc--;
      else tb--, tc++;
      if(tb < 0 || tc < 0) ans = false;
    }
    if(x != 'B' && y != 'B'){
      if(ta == tc && i < n-1){
        if(nx == 'A' || ny == 'A') ta++, tc--;
        else ta--, tc++;
      }
      else if(ta < tc) ta++, tc--;
      else ta--, tc++;
      if(ta < 0 || tc < 0) ans = false;
    }
    if(x != 'C' && y != 'C'){
      if(tb == ta && i < n-1){
        if(nx == 'B' || ny == 'B') tb++, ta--;
        else tb--, ta++;
      }
      else if(tb < ta) tb++, ta--;
      else tb--, ta++;
      if(tb < 0 || ta < 0) ans = false;
    }
  }
  
  if(ans){
    cout << "Yes" << endl;
    for(int i = 0; i < n; ++i){
      char x = s.at(i).at(0), y = s.at(i).at(1);
      if(i < n-1) char nx = s.at(i+1).at(0), ny = s.at(i+1).at(1);
      if(x != 'A' && y != 'A'){
        if(b == c && i < n-1){
          if(nx == 'B' || ny == 'B'){
            b++, c--;
            cout << 'B' << endl;
            continue;
          }
          else{
            b--, c++;
            cout << 'C' << endl;
            continue;
          }
        }
        else if(b < c){
          b++, c--;
          cout << 'B' << endl;
          continue;
        }
        b--, c++;
        cout << 'C' << endl;
      }
      if(x != 'B' && y != 'B'){
        if(a == c && i < n-1){
          if(nx == 'A' || ny == 'A'){
            a++, c--;
            cout << 'A' << endl;
            continue;
          }
          else{
            a--, c++;
            cout << 'C' << endl;
            continue;
          }
        }
        else if(a < c){
      　  a++, c--;
          cout << 'A' << endl;
          continue;
        }
        a--, c++;
        cout << 'C' << endl;
      }
      if(x != 'C' && y != 'C'){
        if(b == a && i < n-1){
          if(nx == 'B' || ny == 'B'){
            b++, a--;
            cout << 'B' << endl;
            continue;
          }
          else{
            b--, a++;
            cout << 'A' << endl;
            continue;
          }
        }
        else if(b < a){
          b++, a--;
          cout << 'B' << endl;
          continue;
        }
        b--, a++;
        cout << 'A' << endl;
      }
    }
  }
  else cout << "No" << endl;
}

Compiler output:
a.cc:84:7: error: extended character 　 is not valid in an identifier
   84 |       　  a++, c--;
      |       ^
a.cc: In function 'int main()':
a.cc:17:12: error: 'nx' was not declared in this scope; did you mean 'x'?
   17 |         if(nx == 'B' || ny == 'B') tb++, tc--;
      |            ^~
      |            x
a.cc:17:25: error: 'ny' was not declared in this scope; did you mean 'y'?
   17 |         if(nx == 'B' || ny == 'B') tb++, tc--;
      |                         ^~
      |                         y
a.cc:26:12: error: 'nx' was not declared in this scope; did you mean 'x'?
   26 |         if(nx == 'A' || ny == 'A') ta++, tc--;
      |            ^~
      |            x
a.cc:26:25: error: 'ny' was not declared in this scope; did you mean 'y'?
   26 |         if(nx == 'A' || ny == 'A') ta++, tc--;
      |                         ^~
      |                         y
a.cc:35:12: error: 'nx' was not declared in this scope; did you mean 'x'?
   35 |         if(nx == 'B' || ny == 'B') tb++, ta--;
      |            ^~
      |            x
a.cc:35:25: error: 'ny' was not declared in this scope; did you mean 'y'?
   35 |         if(nx == 'B' || ny == 'B') tb++, ta--;
      |                         ^~
      |                         y
a.cc:51:14: error: 'nx' was not declared in this scope; did you mean 'x'?
   51 |           if(nx == 'B' || ny == 'B'){
      |              ^~
      |              x
a.cc:51:27: error: 'ny' was not declared in this scope; did you mean 'y'?
   51 |           if(nx == 'B' || ny == 'B'){
      |                           ^~
      |                           y
a.cc:72:14: error: 'nx' was not declared in this scope; did you mean 'x'?
   72 |           if(nx == 'A' || ny == 'A'){
      |              ^~
      |              x
a.cc:72:27: error: 'ny' was not declared in this scope; did you mean 'y'?
   72 |           if(nx == 'A' || ny == 'A'){
      |                           ^~
      |                           y
a.cc:84:7: error: '\U00003000' was not declared in this scope
   84 |       　  a++, c--;
      |       ^~
a.cc:93:14: error: 'nx' was not declared in this scope; did you mean 'x'?
   93 |           if(nx == 'B' || ny == 'B'){
      |              ^~
      |              x
a.cc:93:27: error: 'ny' was not declared in this scope; did you mean 'y'?
   93 |           if(nx == 'B' || ny == 'B'){
      |                           ^~
      |                           y