Problem p02651 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<ll, ll>;
using Pld = pair<ld, ld>;
using Vec = vector<ll>;
using VecP = vector<P>;
using VecB = vector<bool>;
using VecC = vector<char>;
using VecD = vector<ld>;
using VecS = vector<string>;
using Graph = vector<VecP>;
template <typename T> using Vec1 = vector<T>;
template <typename T> using Vec2 = vector<Vec1<T>>;
#define REP(i, m, n) for (ll i = (m); (i) < (n); ++(i))
#define REPN(i, m, n) for (ll i = (m); (i) <= (n); ++(i))
#define REPR(i, m, n) for (ll i = (m)-1; (i) >= (n); --(i))
#define REPNR(i, m, n) for (ll i = (m); (i) >= (n); --(i))
#define rep(i, n) REP(i, 0, n)
#define repn(i, n) REPN(i, 1, n)
#define repr(i, n) REPR(i, n, 0)
#define repnr(i, n) REPNR(i, n, 1)
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define fs first
#define sc second
template <typename T> bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> bool chmin(T &a, const T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> ll pow2(const T n) { return (1LL << n); }
template <typename T> void cosp(const T n) { cout << n << ' '; }
void co(void) { cout << '\\n'; }
template <typename T> void co(const T n) { cout << n << '\\n'; }
template <typename T1, typename T2> void co(pair<T1, T2> p) {
  cout << p.fs << ' ' << p.sc << '\\n';
}
template <typename T> void co(const Vec1<T> &v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void co(initializer_list<T> v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void ce(const T n) { cerr << n << endl; }
void sonic() {
  ios::sync_with_stdio(false);
  cin.tie(0);
}
void setp(const ll n) { cout << fixed << setprecision(n); }
constexpr int INF = 1e9 + 1;
constexpr ll LINF = 1e18 + 1;
constexpr ll MOD = 1e9 + 7;
// constexpr ll MOD = 998244353;
constexpr ld EPS = 1e-11;
const ld PI = acos(-1);

void solve() {
  ll n;
  cin >> n;
  Vec a(n);
  rep(i, n) cin >> a[i];
  string s;
  cin >> s;

  Vec b;
  repr(i, n) {
    ll v = a[i];
    for (ll j : b)
      chmin(v, v ^ j);
    if (v) {
      if (s[i] == '1') {
        co(1);
        return;
      }
      b.pb(v);
    }
  }
  co(0);
}

int main(void) {
  ll t;
  cin >> t;
  rep(i, t) solve();

  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<ll, ll>;
using Pld = pair<ld, ld>;
using Vec = vector<ll>;
using VecP = vector<P>;
using VecB = vector<bool>;
using VecC = vector<char>;
using VecD = vector<ld>;
using VecS = vector<string>;
using Graph = vector<VecP>;
template <typename T> using Vec1 = vector<T>;
template <typename T> using Vec2 = vector<Vec1<T>>;
#define REP(i, m, n) for (ll i = (m); (i) < (n); ++(i))
#define REPN(i, m, n) for (ll i = (m); (i) <= (n); ++(i))
#define REPR(i, m, n) for (ll i = (m)-1; (i) >= (n); --(i))
#define REPNR(i, m, n) for (ll i = (m); (i) >= (n); --(i))
#define rep(i, n) REP(i, 0, n)
#define repn(i, n) REPN(i, 1, n)
#define repr(i, n) REPR(i, n, 0)
#define repnr(i, n) REPNR(i, n, 1)
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define fs first
#define sc second
template <typename T> bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> bool chmin(T &a, const T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> ll pow2(const T n) { return (1LL << n); }
template <typename T> void cosp(const T n) { cout << n << ' '; }
void co(void) { cout << '\\n'; }
template <typename T> void co(const T n) { cout << n << '\\n'; }
template <typename T1, typename T2> void co(pair<T1, T2> p) {
  cout << p.fs << ' ' << p.sc << '\\n';
}
template <typename T> void co(const Vec1<T> &v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void co(initializer_list<T> v) {
  for (T i : v)
    cosp(i);
  co();
}
template <typename T> void ce(const T n) { cerr << n << endl; }
void sonic() {
  ios::sync_with_stdio(false);
  cin.tie(0);
}
void setp(const ll n) { cout << fixed << setprecision(n); }
constexpr int INF = 1e9 + 1;
constexpr ll LINF = 1e18 + 1;
constexpr ll MOD = 1e9 + 7;
// constexpr ll MOD = 998244353;
constexpr ld EPS = 1e-11;
const ld PI = acos(-1);

void solve() {
  ll n;
  cin >> n;
  Vec a(n);
  rep(i, n) cin >> a[i];
  string s;
  cin >> s;

  unordered_set<ll> ust;
  ust.insert(0);
  repr(i, n) {
    if (s[i] == '0') {
      unordered_set<ll> nxt;
      for (ll j : ust) {
        nxt.insert(j);
        nxt.insert(j ^ a[i]);
      }
      swap(nxt, ust);
    } else {
      unordered_set<ll> nxt;
      for (ll j : ust)
        if (ust.find(j ^ a[i]) != ust.end())
          nxt.insert(j);
      swap(nxt, ust);
    }
  }

  if (ust.find(0) == ust.end())
    co(1);
  else
    co(0);
}

int main(void) {
  ll t;
  cin >> t;

  rep(i, t) solve();

  return 0;
}