Problem p02649 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
// #define ll __int128
// #define int ll
// #define int ll
// #define char ll
#define double ld
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(), a.end()
#define RALL(a) a.rbegin(), a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for (int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr                                                                   \\
  if (false)                                                                   \\
  cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";

template <class T0, class T1>
inline ostream &operator<<(ostream &out, pair<T0, T1> &a) {
  return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream &operator>>(istream &in, pair<T0, T1> &a) {
  return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2, T3> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << ", " << get<3>(a) << "}";
}

template <class T> inline ostream &operator<<(ostream &out, vector<T> &a) {
  out << "[";
  fori(i, a.size()) out << a[i]
                        << vector<string>{", ", "]  "}[i + 1 == a.size()];
  return out;
}

void smain();

signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifdef MAX_HOME
  freopen("input.txt", "r", stdin);
  clock_t start = clock();
#endif
  cout << setprecision(12) << fixed;
  smain();
#ifdef MAX_HOME
  cout << "\\n\\nTOTAL EXECUTION TIME: "
       << float(clock() - start) / CLOCKS_PER_SEC << endl;
#endif
  return 0;
}

const int L = 18;

const int K = 26;
const int N = 52;

void estimate() {
  int n = 50;
  ll ans = 0;
  fori(i, n) {
    fori(j, i) {
      fori(k, j) { ans += 1 << 18; }
    }
  }
  cerr << ans / 1e8;
  exit(0);
}

vector<pair<int, ll>> dp[N][N];

ll cdp[N][1 << L];

void smain() {

  //    estimate();

  int n, k, s, t;
  cin >> n >> k >> s >> t;
  vi a(n);
  fori(i, n) { cin >> a[i]; }

  vi ids;

  fori(b, L) {
    if (((s >> b) & 1) && !((t >> b) & 1)) {
      cout << 0;
      return;
    }
    if (((s >> b) & 1) == ((t >> b) & 1)) {
      vi tmp;
      ids.push_back(b);
      for (auto x : a) {
        if (((x >> b) & 1) == ((s >> b) & 1)) {
          tmp.push_back(x);
        }
      }
      a = tmp;
    }
  }
  set<int> idsset(ALL(ids));
  for (auto &x : a) {
    for (int i = L - 1; i >= 0; --i) {
      if (idsset.count(i)) {
        x = (x & ((1 << i) - 1)) + ((x >> i + 1) << i);
      }
    }
  }
  int len = L - (int)idsset.size();
  vl ans(n + 1, 0);
  fori(i, a.size()) {
    cdp[1][0] = 1;
    fori(j, i) {
      fori(k, j + 2) {
        if (k + 1 < N)
          for (auto x : dp[j][k]) {
            int mask = x.first;
            ll val = x.second;
            cdp[k + 1][mask | (a[i] ^ a[j])] += val;
          }
      }
    }
    fori(k, i + 2) {
      ans[k] += cdp[k][(1 << len) - 1];
      fori(mask, 1 << len) {
        if (cdp[k][mask]) {
          dp[i][k].push_back({mask, cdp[k][mask]});
          cdp[k][mask] = 0;
        }
      }
      //            cerr << "dp[" << i << "][" << k << "] = " << dp[i][k] <<
      //            endl;
    }
  }
  //    watch(ans);
  ll kek = 0;
  for (int i = 1; i <= k; ++i) {
    kek += ans[i];
  }
  cout << kek;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
// #define ll __int128
// #define int ll
// #define int ll
// #define char ll
#define double ld
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(), a.end()
#define RALL(a) a.rbegin(), a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for (int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr                                                                   \\
  if (false)                                                                   \\
  cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";

template <class T0, class T1>
inline ostream &operator<<(ostream &out, pair<T0, T1> &a) {
  return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream &operator>>(istream &in, pair<T0, T1> &a) {
  return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2, T3> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << ", " << get<3>(a) << "}";
}

template <class T> inline ostream &operator<<(ostream &out, vector<T> &a) {
  out << "[";
  fori(i, a.size()) out << a[i]
                        << vector<string>{", ", "]  "}[i + 1 == a.size()];
  return out;
}

void smain();

signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifdef MAX_HOME
  freopen("input.txt", "r", stdin);
  clock_t start = clock();
#endif
  cout << setprecision(12) << fixed;
  smain();
#ifdef MAX_HOME
  cout << "\\n\\nTOTAL EXECUTION TIME: "
       << float(clock() - start) / CLOCKS_PER_SEC << endl;
#endif
  return 0;
}

const int L = 18;

void sosdp() {
  //    for (int i = 0; i < (1 << N); ++i)
  //        F[i] = A[i];
  //    for (int i = 0; i < N; ++i)
  //        for (int mask = 0; mask < (1 << N); ++mask)
  //            if (mask & (1 << i)) F[mask] += F[mask ^ (1 << i)];
}

const int K = 26;
// 0 good
// 1 bad
int F[K][1 << L];

void smain() {

  int n, k, s, t;
  cin >> n >> k >> s >> t;
  vi a(n);
  fori(i, n) { cin >> a[i]; }

  vi ids;

  fori(b, L) {
    if (((s >> b) & 1) && !((t >> b) & 1)) {
      cout << 0;
      return;
    }
    if (((s >> b) & 1) == ((t >> b) & 1)) {
      vi tmp;
      ids.push_back(b);
      for (auto x : a) {
        if (((x >> b) & 1) == ((s >> b) & 1)) {
          tmp.push_back(x);
        }
      }
      a = tmp;
    }
  }
  set<int> idsset(ALL(ids));
  for (auto &x : a) {
    for (int i = L - 1; i >= 0; --i) {
      if (idsset.count(i)) {
        x = (x & ((1 << i) - 1)) + ((x >> i + 1) << i);
      }
    }
  }
  int len = L - (int)idsset.size();

  ll ans = 0;

  n = a.size();

  int h = n - 1 >> 1;
  int h2 = n - 1 - h;
  while (a.size()) {
    if (h <= 0) {
      n = a.size();
      fori(mask, 1 << n) if (__builtin_popcount(mask) <= k) {
        if (!mask)
          continue;
        int s = (1 << len) - 1;
        int t = 0;
        fori(i, n) if ((mask >> i) & 1) {
          s &= a[i];
          t |= a[i];
        }
        ans += (s == 0 && t == ((1 << len) - 1));
      }
      break;
    }
    reverse(ALL(a));
    int zer = a.back();
    a.pop_back();
    reverse(ALL(a));
    n = a.size();
    vi b;
    for (auto x : a) {
      fori(i, len) {
        if (((x >> i) & 1) == ((zer >> i) & 1)) {
          if (!((x >> i) & 1)) {
            x += 1 << i;
          }
        } else {
          if ((x >> i) & 1) {
            x -= 1 << i;
          }
        }
      }
      b.push_back(x);
    }

    fori(mask, 1 << h2) {
      int cnt = 0;
      int cmask = (1 << len) - 1;
      fori(i, h2) if ((mask >> i) & 1) {
        cnt++;
        cmask &= b[i + h];
      }
      F[cnt][cmask]++;
    }

    for (int cnt = 0; cnt <= h2; ++cnt) {

      for (int i = 0; i < len; ++i)
        for (int mask = 0; mask < (1 << len); ++mask)
          if (mask & (1 << i))
            F[cnt][mask] += F[cnt][mask ^ (1 << i)];
    }

    for (int cnt = 1; cnt <= h2; ++cnt) {
      for (int mask = 0; mask < (1 << len); ++mask) {
        F[cnt][mask] += F[cnt - 1][mask];
      }
    }

    fori(mask, 1 << h) {
      int cnt = 0;
      int cmask = (1 << len) - 1;
      fori(i, h) {
        if ((mask >> i) & 1) {
          cnt++;
          cmask &= b[i];
        }
      }
      cmask = ((1 << len) - 1) ^ cmask;
      int kek = k - 1 - cnt;
      inmin(kek, h2);
      if (kek >= 0)
        ans += F[kek][cmask];
    }

    for (int i = 0; i <= h2; ++i) {
      fori(mask, (1 << len)) { F[i][mask] = 0; }
    }
    h--;
  }

  cout << ans;
}