Problem p02940 (C++)

Buggy submission (status: Runtime Error):
// marico el que lo lea
#include <algorithm>
#include <assert.h>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <stdlib.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> ii;

void fastIO() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}

#define pb push_back
#define all(obj) obj.begin(), obj.end()
#define ms(obj, val) memset(obj, val, sizeof(obj))
#define ms2(obj, val, sz) memset(obj, val, sizeof(obj[0]) * sz)

#define fst first
#define snd second

template <typename T, typename U> inline void mnze(T &x, U y) {
  if (y < x)
    x = y;
}
template <typename T, typename U> inline void mxze(T &x, U y) {
  if (x < y)
    x = y;
}

void _scan(int &x) { scanf("%d", &x); }
void _scan(long long &x) { scanf("%lld", &x); }
void _scan(double &x) { scanf("%lf", &x); }
void _scan(char &x) { scanf(" %c", &x); }
void _scan(char *x) { scanf("%s", x); }
template <typename T> void _scan(vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++)
    _scan(v[i]);
}
void scan() {}
template <typename T, typename... U> void scan(T &head, U &...tail) {
  _scan(head);
  scan(tail...);
}

template <typename T> void _dbg(const char *sdbg, T h) {
  cerr << sdbg << "=" << h << "\n";
}
template <typename T, typename... U> void _dbg(const char *sdbg, T h, U... t) {
  while (*sdbg != ',')
    cerr << *sdbg++;
  cerr << "=" << h << ",";
  _dbg(sdbg + 1, t...);
}

#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x)                                                              \
  {                                                                            \
    {                                                                          \
      cerr << #x << " = ";                                                     \
      for (auto _i : x)                                                        \
        cerr << _i << ", ";                                                    \
      cerr << "\n";                                                            \
    }                                                                          \
  }
#define debuga(x, sz)                                                          \
  {                                                                            \
    {                                                                          \
      cerr << #x << " = ";                                                     \
      for (int _i = 0; _i < sz; _i++)                                          \
        cerr << x[_i] << ", ";                                                 \
      cerr << "\n";                                                            \
    }                                                                          \
  }
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define debuga(x, sz)
#define cerr                                                                   \
  if (0)                                                                       \
  cout
#endif

ll MOD = 998244353;

inline ll Msum(ll x) { return x; }
template <typename... Rest> inline ll Msum(ll x, Rest... rest) {
  return (x + Msum(rest...)) % MOD;
}

inline ll Mprod(ll x) { return x; }
template <typename... Rest> inline ll Mprod(ll x, Rest... rest) {
  return x * Mprod(rest...) % MOD;
}

inline ll Mnorm(ll x) { return (x % MOD + MOD) % MOD; }

inline ll Msq(ll x) { return (x * x) % MOD; }
inline ll Mpot(ll x, ll e) {
  if (!e)
    return 1;
  return Msq(Mpot(x, e >> 1)) * (e & 1 ? x : 1) % MOD;
}
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

const int MAXN = 1e5 + 5;

int n, a[MAXN];
char s[MAXN];

ll cnt[3], comp[3];

int other(int x, int y) {
  if (x > y)
    swap(x, y);
  if (x == 0) {
    if (y == 1)
      return 2;
    return 1;
  }
  if (x == 1) {
    assert(y == 2);
    return 0;
  }
  assert(false);
}

int main() {
  int m[300];
  m['R'] = 0;
  m['G'] = 1;
  m['B'] = 2;

  scan(n, s);
  for (int i = 0; i < 3 * n; i++)
    a[i] = m[(int)s[i]];

  ll ans = 1;

  for (int i = 2; i < n + 1; i++)
    ans = Mprod(ans, i);

  for (int i = 0; i < 3 * n; i++) {
    int x = a[i];
    if (comp[x]) {
      ans = Mprod(comp[x], ans);
      comp[x]--;
    } else {
      bool found = false;
      for (int y = 0; y < 3; y++)
        if (y != x && cnt[y] > 0) {
          found = true;
          ans = Mprod(ans, cnt[y]);
          cnt[y]--;
          comp[other(x, y)]++;
          break;
        }
      if (!found) {
        cnt[x]++;
      }
    }
  }

  printf("%lld\n", ans);
}


Fixed submission:
// marico el que lo lea
#include <algorithm>
#include <assert.h>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <stdlib.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> ii;

void fastIO() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}

#define pb push_back
#define all(obj) obj.begin(), obj.end()
#define ms(obj, val) memset(obj, val, sizeof(obj))
#define ms2(obj, val, sz) memset(obj, val, sizeof(obj[0]) * sz)

#define fst first
#define snd second

template <typename T, typename U> inline void mnze(T &x, U y) {
  if (y < x)
    x = y;
}
template <typename T, typename U> inline void mxze(T &x, U y) {
  if (x < y)
    x = y;
}

void _scan(int &x) { scanf("%d", &x); }
void _scan(long long &x) { scanf("%lld", &x); }
void _scan(double &x) { scanf("%lf", &x); }
void _scan(char &x) { scanf(" %c", &x); }
void _scan(char *x) { scanf("%s", x); }
template <typename T> void _scan(vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++)
    _scan(v[i]);
}
void scan() {}
template <typename T, typename... U> void scan(T &head, U &...tail) {
  _scan(head);
  scan(tail...);
}

template <typename T> void _dbg(const char *sdbg, T h) {
  cerr << sdbg << "=" << h << "\n";
}
template <typename T, typename... U> void _dbg(const char *sdbg, T h, U... t) {
  while (*sdbg != ',')
    cerr << *sdbg++;
  cerr << "=" << h << ",";
  _dbg(sdbg + 1, t...);
}

#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x)                                                              \
  {                                                                            \
    {                                                                          \
      cerr << #x << " = ";                                                     \
      for (auto _i : x)                                                        \
        cerr << _i << ", ";                                                    \
      cerr << "\n";                                                            \
    }                                                                          \
  }
#define debuga(x, sz)                                                          \
  {                                                                            \
    {                                                                          \
      cerr << #x << " = ";                                                     \
      for (int _i = 0; _i < sz; _i++)                                          \
        cerr << x[_i] << ", ";                                                 \
      cerr << "\n";                                                            \
    }                                                                          \
  }
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define debuga(x, sz)
#define cerr                                                                   \
  if (0)                                                                       \
  cout
#endif

ll MOD = 998244353;

inline ll Msum(ll x) { return x; }
template <typename... Rest> inline ll Msum(ll x, Rest... rest) {
  return (x + Msum(rest...)) % MOD;
}

inline ll Mprod(ll x) { return x; }
template <typename... Rest> inline ll Mprod(ll x, Rest... rest) {
  return x * Mprod(rest...) % MOD;
}

inline ll Mnorm(ll x) { return (x % MOD + MOD) % MOD; }

inline ll Msq(ll x) { return (x * x) % MOD; }
inline ll Mpot(ll x, ll e) {
  if (!e)
    return 1;
  return Msq(Mpot(x, e >> 1)) * (e & 1 ? x : 1) % MOD;
}
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

const int MAXN = 3e5 + 5;

int n, a[MAXN];
char s[MAXN];

ll cnt[3], comp[3];

int other(int x, int y) {
  if (x > y)
    swap(x, y);
  if (x == 0) {
    if (y == 1)
      return 2;
    return 1;
  }
  if (x == 1) {
    assert(y == 2);
    return 0;
  }
  assert(false);
}

int main() {
  int m[300];
  m['R'] = 0;
  m['G'] = 1;
  m['B'] = 2;

  scan(n, s);
  for (int i = 0; i < 3 * n; i++)
    a[i] = m[(int)s[i]];

  ll ans = 1;

  for (int i = 2; i < n + 1; i++)
    ans = Mprod(ans, i);

  for (int i = 0; i < 3 * n; i++) {
    int x = a[i];
    if (comp[x]) {
      ans = Mprod(comp[x], ans);
      comp[x]--;
    } else {
      bool found = false;
      for (int y = 0; y < 3; y++)
        if (y != x && cnt[y] > 0) {
          found = true;
          ans = Mprod(ans, cnt[y]);
          cnt[y]--;
          comp[other(x, y)]++;
          break;
        }
      if (!found) {
        cnt[x]++;
      }
    }
  }

  printf("%lld\n", ans);
}