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

/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

// doot diddly donger cuckerino Hahahahahah
// Created by White Knife on 15/04/20.
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
#pragma GCC target("popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace __gnu_cxx;
using namespace std;

// @formatter:off
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
#define sz(x) (long long)(x).size()
#define sim template <typename T
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \\
  sim > typename enable_if<sizeof dud<T>(0) x 1, debug &>::type operator<<(T i)
sim > struct rge {
  T b, e;
};
sim > rge<T> range(T i, T j) { return rge<T>{i, j}; }
sim > auto dud(T *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) {
    cerr << boolalpha << i;
    ris;
  }
  eni(==) { ris << range(all(i)); }
  sim, typename U dor(pair<U, T> d) {
    ris << "(" << d.first << ", " << d.second << ")";
  }
  sim dor(rge<T> d) {
    *this << "[";
    for (auto it = d.b; it != d.e; ++it)
      *this << ", " + 2 * (it == d.b) << *it;
    ris << "]";
  }
#else
  sim dor(const T &) { ris; }
#endif
};
#define pr(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vb = vector<bool>;

using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vpll = vector<pll>;
template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ld PI = acos(-1);

template <typename T> T gcd(T x, T y) { return (y == 0) ? x : gcd(y, x % y); }
template <typename T> inline T mini(T &x, T y) { return x = min(x, y); }
template <typename T> inline T maxi(T &x, T y) { return x = max(x, y); }
template <typename T> T rand(T x, T y) { return rand() % (y - x + 1) + x; }
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
// @formatter:on

class FThreeVariablesGame {
public:
  void solveOne(istream &cin, ostream &cout) {}

  void solve(std::istream &cin, std::ostream &cout) {
    int n;
    cin >> n;
    vi arr(3);
    for (int i = 0; i < 3; ++i) {
      cin >> arr[i];
    }
    vector<string> s(n);
    for (int i = 0; i < n; ++i) {
      cin >> s[i];
    }
    string ans(n, 'A');
    for (int i = 0; i < n; ++i) {
      int a = s[i][0] - 'A', b = s[i][1] - 'A';
      if (arr[a] == 0 and arr[b] == 0) {
        cout << "No\\n";
        return;
      } else if (arr[a] > arr[b]) {
        ans[i] += b;
        arr[a]--, arr[b]++;
      } else if (arr[b] > arr[a]) {
        ans[i] += a;
        arr[a]++, arr[b]--;
      } else {
        if (i == n - 1 || s[i] == s[i + 1]) {
          ans[i] += a;
          arr[a]++, arr[b]--;
        } else {
          int c = s[i + 1][0] - 'A', d = s[i + 1][1] - 'A';
          if (a == c || a == d) {
            ans[i] += a;
            arr[a]++, arr[b]--;
          } else {
            ans[i] += b;
            arr[a]--, arr[b]++;
          }
        }
      }
    }
    cout << "Yes" << '\\n';
    for (char c : ans) {
      cout << c << '\\n';
    }
  }
};

int main() {
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);
  FThreeVariablesGame solver;
  std::istream &in(std::cin);
  std::ostream &out(std::cout);
  solver.solve(in, out);
  return 0;
}


Error: 0

Fixed submission:

/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

// doot diddly donger cuckerino Hahahahahah
// Created by White Knife on 15/04/20.
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
#pragma GCC target("popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace __gnu_cxx;
using namespace std;

// @formatter:off
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
#define sz(x) (long long)(x).size()
#define sim template <typename T
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \\
  sim > typename enable_if<sizeof dud<T>(0) x 1, debug &>::type operator<<(T i)
sim > struct rge {
  T b, e;
};
sim > rge<T> range(T i, T j) { return rge<T>{i, j}; }
sim > auto dud(T *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) {
    cerr << boolalpha << i;
    ris;
  }
  eni(==) { ris << range(all(i)); }
  sim, typename U dor(pair<U, T> d) {
    ris << "(" << d.first << ", " << d.second << ")";
  }
  sim dor(rge<T> d) {
    *this << "[";
    for (auto it = d.b; it != d.e; ++it)
      *this << ", " + 2 * (it == d.b) << *it;
    ris << "]";
  }
#else
  sim dor(const T &) { ris; }
#endif
};
#define pr(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vb = vector<bool>;

using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vpll = vector<pll>;
template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ld PI = acos(-1);

template <typename T> T gcd(T x, T y) { return (y == 0) ? x : gcd(y, x % y); }
template <typename T> inline T mini(T &x, T y) { return x = min(x, y); }
template <typename T> inline T maxi(T &x, T y) { return x = max(x, y); }
template <typename T> T rand(T x, T y) { return rand() % (y - x + 1) + x; }
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
// @formatter:on

class FThreeVariablesGame {
public:
  void solveOne(istream &cin, ostream &cout) {}

  void solve(std::istream &cin, std::ostream &cout) {
    int n;
    cin >> n;
    vi arr(3);
    for (int i = 0; i < 3; ++i) {
      cin >> arr[i];
    }
    vector<string> s(n);
    for (int i = 0; i < n; ++i) {
      cin >> s[i];
    }
    string ans(n, 'A');
    for (int i = 0; i < n; ++i) {
      int a = s[i][0] - 'A', b = s[i][1] - 'A';
      if (arr[a] == 0 and arr[b] == 0) {
        cout << "No\\n";
        return;
      } else if (arr[a] > arr[b]) {
        ans[i] += b;
        arr[a]--, arr[b]++;
      } else if (arr[b] > arr[a]) {
        ans[i] += a;
        arr[a]++, arr[b]--;
      } else {
        int c = s[i + 1][0] - 'A', d = s[i + 1][1] - 'A';
        if (a == c || a == d) {
          ans[i] += a;
          arr[a]++, arr[b]--;
        } else {
          ans[i] += b;
          arr[a]--, arr[b]++;
        }
      }
    }
    cout << "Yes" << '\\n';
    for (char c : ans) {
      cout << c << '\\n';
    }
  }
};

int main() {
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);
  FThreeVariablesGame solver;
  std::istream &in(std::cin);
  std::ostream &out(std::cout);
  solver.solve(in, out);
  return 0;
}