Problem p02692 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
using Real = long double;
using Point = complex<Real>; // Point and Vector2d is the same!
using Vector2d = complex<Real>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
const double EPS = 1e-15;
const double PI = 3.14159265358979323846;
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
istream &operator>>(istream &is, Point &p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \\
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \\
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \\
          << "    ",                                                           \\
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif
void muri() {
  print("No");
  exit(0);
}
signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, a, b, c;
  cin >> n >> a >> b >> c;
  string s = "";
  vector<string> q(n);
  rep(i, n) {
    string tmp;
    cin >> tmp;
    q[i] = tmp;
  }
  rep(i, n) {
    string tmp = q[i];

    if (tmp == "AB") {

      if (a + b == 0)
        muri();
      if (a == 1 && b == 1 && i != n - 1) {
        if (q[i + 1] != tmp) {
          if (q[i + 1][0] == 'A') {
            a++, b--;
            s += "A";
            continue;
          } else {
            a--, b++;
            s += "B";
            continue;
          }
        }
      }
      if (a < b)
        a++, b--, s += "A";
      else
        a--, b++, s += "B";
    }
    if (tmp == "BC") {
      if (c + b == 0)
        muri();
      if (c == 1 && b == 1 && i != n - 1) {
        if (q[i + 1] != tmp) {
          if (q[i + 1][1] == 'C') {
            c++, b--;
            s += "C";
            continue;
          } else {
            c--, b++;
            s += "B";
            continue;
          }
        }
      }
      if (b < c)
        b++, c--, s += "B";
      else
        b--, c++, s += "C";
    }
    if (tmp == "AC") {
      if (a + c == 0)
        muri();
      if (c == 1 && a == 1 && i != n - 1) {
        if (q[i + 1] != tmp) {
          if (q[i + 1][1] == 'C') {
            c++, a--;
            s += "C";
            continue;
          } else {
            c--, a++;
            s += "A";
            continue;
          }
        }
      }
      if (a < c)
        a++, c--, s += "A";
      else
        a--, c++, s += "C";
    }
    if (a < 0 || b < 0 || c < 0) {
      print("No");
      return 0;
    }
  }

  print("Yes");

  rep(i, n) { print(s[i]); }
}


Error: WA

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
using Real = long double;
using Point = complex<Real>; // Point and Vector2d is the same!
using Vector2d = complex<Real>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
const double EPS = 1e-15;
const double PI = 3.14159265358979323846;
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
istream &operator>>(istream &is, Point &p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \\
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \\
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \\
          << "    ",                                                           \\
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, a, b, c;
  cin >> n >> a >> b >> c;
  string s = "";
  rep(i, n) {
    string s;
    cin >> s;
    if (s == "AB") {
      if (a < b)
        a++, b--, s += 'A';
      else
        a--, b++, s += 'B';
    }
    if (s == "BC") {
      if (b < c)
        b++, c--, s += 'B';
      else
        b--, c++, s += 'C';
    }
    if (s == "AC") {
      if (a < c)
        a++, c--, s += 'A';
      else
        a--, c++, s += 'C';
    }
    if (a < 0 || b < 0 || c < 0) {
      print("No");
      return 0;
    }
  }
  print("Yes");
  rep(i, n) { print(s[i]); }
}