Problem p03562 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define rng(a) a.begin(), a.end()
#define rrng(a) a.rbegin(), a.rend()
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define limit(x, l, r) max(l, min(x, r))
#define lims(x, l, r) (x = max(l, min(x, r)))
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define eb emplace_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)), x.end())
#define snuke srand((unsigned)clock() + (unsigned)time(NULL));
#define show(x) cout << #x << " = " << x << endl;
#define PQ(T) priority_queue<T, v(T), greater<T>>
#define bn(x) ((1 << x) - 1)
#define dup(x, y) (((x) + (y)-1) / (y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
typedef vector<T> vt;
inline int getInt() {
  int x;
  scanf("%d", &x);
  return x;
}
template <typename T> inline istream &operator>>(istream &i, v(T) & v) {
  rep(j, sz(v)) i >> v[j];
  return i;
}
template <typename T> string join(const v(T) & v) {
  stringstream s;
  rep(i, sz(v)) s << ' ' << v[i];
  return s.str().substr(1);
}
template <typename T> inline ostream &operator<<(ostream &o, const v(T) & v) {
  if (sz(v))
    o << join(v);
  return o;
}
template <typename T1, typename T2>
inline istream &operator>>(istream &i, pair<T1, T2> &v) {
  return i >> v.fi >> v.se;
}
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> &v) {
  return o << v.fi << "," << v.se;
}
template <typename T> inline ll suma(const v(T) & a) {
  ll res(0);
  for (auto &&x : a)
    res += x;
  return res;
}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame                                                                   \
  {                                                                            \
    puts("-1");                                                                \
    return 0;                                                                  \
  }
#define yn                                                                     \
  { puts("Yes"); }                                                             \
  else {                                                                       \
    puts("No");                                                                \
  }
const int MX = 20;
typedef v(string) vs;

// Mod int
const int mod = 998244353;
struct mint {
  ll x;
  mint() : x(0) {}
  mint(ll x) : x((x % mod + mod) % mod) {}
  // mint(ll x):x(x){}
  mint &fix() {
    x = (x % mod + mod) % mod;
    return *this;
  }
  mint operator-() const { return mint(0) - *this; }
  mint operator~() const { return mint(1) / *this; }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator-=(const mint &a) {
    if ((x += mod - a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint &operator/=(const mint &a) {
    (x *= a.pow(mod - 2).x) %= mod;
    return *this;
  }
  mint operator+(const mint &a) const { return mint(*this) += a; }
  mint operator-(const mint &a) const { return mint(*this) -= a; }
  mint operator*(const mint &a) const { return mint(*this) *= a; }
  mint operator/(const mint &a) const { return mint(*this) /= a; }
  mint pow(ll t) const {
    if (!t)
      return 1;
    mint res = pow(t / 2);
    res *= res;
    return (t & 1) ? res * x : res;
  }
  bool operator<(const mint &a) const { return x < a.x; }
  bool operator==(const mint &a) const { return x == a.x; }
};
mint ex(mint x, ll t) { return x.pow(t); }
istream &operator>>(istream &i, mint &a) {
  i >> a.x;
  return i;
}
ostream &operator<<(ostream &o, const mint &a) {
  o << a.x;
  return o;
}
typedef vector<mint> vm;
struct comb {
  vm f, g;
  comb() {}
  comb(int mx) : f(mx + 1), g(mx + 1) {
    f[0] = 1;
    rrep(i, mx) f[i] = f[i - 1] * i;
    g[mx] = f[mx].pow(mod - 2);
    for (int i = mx; i > 0; i--)
      g[i - 1] = g[i] * i;
  }
  mint operator()(int a, int b) {
    if (a < b)
      return 0;
    return f[a] * g[b] * g[a - b];
  }
};
//

struct D {
  bitset<MX> d;
  int n;
  D() : n(0) {}
  D(const string &s) {
    n = sz(s);
    rep(i, n) d[i] = s[n - 1 - i] - '0';
  }
  void sub(const D &a) {
    d ^= a.d << (n - a.n);
    while (n && !d[n - 1])
      --n;
  }
};

D inD() {
  string s;
  cin >> s;
  return D(s);
}

D g(D a, D b) {
  while (1) {
    if (a.n < b.n)
      swap(a, b);
    if (!b.n)
      break;
    a.sub(b);
  }
  return a;
}

int main() {
  int n;
  scanf("%d", &n);
  D x = inD();
  D a = inD();
  rep(i, n - 1) a = g(a, inD());
  mint ans;
  bitset<MX> d;
  for (int i = x.n - 1; i >= a.n - 1; --i) {
    ans = ans * 2 + mint(x.d[i]);
    if (x.d[i] ^ d[i])
      d ^= a.d << (i - a.n + 1);
  }
  int add = 1;
  drep(i, a.n) {
    if (x.d[i] == d[i])
      continue;
    add = x.d[i];
    break;
  }
  ans += add;
  cout << ans << endl;
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define rng(a) a.begin(), a.end()
#define rrng(a) a.rbegin(), a.rend()
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define limit(x, l, r) max(l, min(x, r))
#define lims(x, l, r) (x = max(l, min(x, r)))
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define eb emplace_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)), x.end())
#define snuke srand((unsigned)clock() + (unsigned)time(NULL));
#define show(x) cout << #x << " = " << x << endl;
#define PQ(T) priority_queue<T, v(T), greater<T>>
#define bn(x) ((1 << x) - 1)
#define dup(x, y) (((x) + (y)-1) / (y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
typedef vector<T> vt;
inline int getInt() {
  int x;
  scanf("%d", &x);
  return x;
}
template <typename T> inline istream &operator>>(istream &i, v(T) & v) {
  rep(j, sz(v)) i >> v[j];
  return i;
}
template <typename T> string join(const v(T) & v) {
  stringstream s;
  rep(i, sz(v)) s << ' ' << v[i];
  return s.str().substr(1);
}
template <typename T> inline ostream &operator<<(ostream &o, const v(T) & v) {
  if (sz(v))
    o << join(v);
  return o;
}
template <typename T1, typename T2>
inline istream &operator>>(istream &i, pair<T1, T2> &v) {
  return i >> v.fi >> v.se;
}
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> &v) {
  return o << v.fi << "," << v.se;
}
template <typename T> inline ll suma(const v(T) & a) {
  ll res(0);
  for (auto &&x : a)
    res += x;
  return res;
}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame                                                                   \
  {                                                                            \
    puts("-1");                                                                \
    return 0;                                                                  \
  }
#define yn                                                                     \
  { puts("Yes"); }                                                             \
  else {                                                                       \
    puts("No");                                                                \
  }
const int MX = 4005;
typedef v(string) vs;

// Mod int
const int mod = 998244353;
struct mint {
  ll x;
  mint() : x(0) {}
  mint(ll x) : x((x % mod + mod) % mod) {}
  // mint(ll x):x(x){}
  mint &fix() {
    x = (x % mod + mod) % mod;
    return *this;
  }
  mint operator-() const { return mint(0) - *this; }
  mint operator~() const { return mint(1) / *this; }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator-=(const mint &a) {
    if ((x += mod - a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint &operator/=(const mint &a) {
    (x *= a.pow(mod - 2).x) %= mod;
    return *this;
  }
  mint operator+(const mint &a) const { return mint(*this) += a; }
  mint operator-(const mint &a) const { return mint(*this) -= a; }
  mint operator*(const mint &a) const { return mint(*this) *= a; }
  mint operator/(const mint &a) const { return mint(*this) /= a; }
  mint pow(ll t) const {
    if (!t)
      return 1;
    mint res = pow(t / 2);
    res *= res;
    return (t & 1) ? res * x : res;
  }
  bool operator<(const mint &a) const { return x < a.x; }
  bool operator==(const mint &a) const { return x == a.x; }
};
mint ex(mint x, ll t) { return x.pow(t); }
istream &operator>>(istream &i, mint &a) {
  i >> a.x;
  return i;
}
ostream &operator<<(ostream &o, const mint &a) {
  o << a.x;
  return o;
}
typedef vector<mint> vm;
struct comb {
  vm f, g;
  comb() {}
  comb(int mx) : f(mx + 1), g(mx + 1) {
    f[0] = 1;
    rrep(i, mx) f[i] = f[i - 1] * i;
    g[mx] = f[mx].pow(mod - 2);
    for (int i = mx; i > 0; i--)
      g[i - 1] = g[i] * i;
  }
  mint operator()(int a, int b) {
    if (a < b)
      return 0;
    return f[a] * g[b] * g[a - b];
  }
};
//

struct D {
  bitset<MX> d;
  int n;
  D() : n(0) {}
  D(const string &s) {
    n = sz(s);
    rep(i, n) d[i] = s[n - 1 - i] - '0';
  }
  void sub(const D &a) {
    d ^= a.d << (n - a.n);
    while (n && !d[n - 1])
      --n;
  }
};

D inD() {
  string s;
  cin >> s;
  return D(s);
}

D g(D a, D b) {
  while (1) {
    if (a.n < b.n)
      swap(a, b);
    if (!b.n)
      break;
    a.sub(b);
  }
  return a;
}

int main() {
  int n;
  scanf("%d", &n);
  D x = inD();
  D a = inD();
  rep(i, n - 1) a = g(a, inD());
  mint ans;
  bitset<MX> d;
  for (int i = x.n - 1; i >= a.n - 1; --i) {
    ans = ans * 2 + mint(x.d[i]);
    if (x.d[i] ^ d[i])
      d ^= a.d << (i - a.n + 1);
  }
  int add = 1;
  drep(i, a.n) {
    if (x.d[i] == d[i])
      continue;
    add = x.d[i];
    break;
  }
  ans += add;
  cout << ans << endl;
  return 0;
}