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

#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#define _USE_MATH_DEFINES
#include <complex>
#include <functional>
#include <math.h>
using namespace std;

#define rep(i, x) for (ll i = 0; i < x; i++)
#define repn(i, x) for (ll i = 1; i <= x; i++)

typedef long long ll;
const ll INF = 1e18 + 1e18;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
  if (a > b) {
    return a;
  }
  return b;
}

ll min(ll a, ll b) {
  if (a > b) {
    return b;
  }
  return a;
}

ll gcd(ll a, ll b) {
  if (b == 0) {
    return a;
  }
  if (a < b) {
    return gcd(b, a);
  }
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

struct edge {
  ll ind;
  ll fr;
  ll to;
  ll d;
};

class mint {
  long long x;

public:
  mint(long long x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  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) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint &a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint &a) const {
    mint res(*this);
    return res *= a;
  }

  mint pow(ll t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime MOD
  mint inv() const { return pow(MOD - 2); }
  mint &operator/=(const mint &a) { return (*this) *= a.inv(); }
  mint operator/(const mint &a) const {
    mint res(*this);
    return res /= a;
  }

  friend ostream &operator<<(ostream &os, const mint &m) {
    os << m.x;
    return os;
  }
};

mint pw(mint a, ll b) {
  if (b == 0) {
    return 1;
  }
  mint ret = pw(a, b >> 1);
  ret *= ret;
  if (b & 1) {
    ret *= a;
  }
  return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

//////////////////////////////////////

int main() {
  vvll com(60, vll(60, 0));
  com[0][0] = 1;
  rep(i, 60) rep(j, 60) {
    if (i > 0)
      com[i][j] += com[i - 1][j];
    if (i > 0 && j > 0) {
      com[i][j] += com[i - 1][j - 1];
    }

    // cout << i << " " << j << " " << com[i][j] << endl;
  }

  ll N, K, S, T;
  cin >> N >> K >> S >> T;
  vll A(N, 0);
  rep(i, N) cin >> A[i];

  ll M = 18;
  vll b(M + 1, 0);

  rep(i, N) repn(j, M) {
    if ((A[i] >> (j - 1)) & 1) {
      b[j] += 1ull << i;
    }
  }

  // repn(j, M)cout << b[j] << endl;

  vector<vector<pair<ll, ll>>> dpp(M + 1);
  dpp[0].push_back({0, (1ull << N) - 1});

  repn(i, M) {

    for (auto x : dpp[i - 1]) {
      ll j = x.first;
      ll y = x.second;

      if (y > 0)
        dpp[i].push_back({3 * j, y});
      if ((y & b[i]) > 0)
        dpp[i].push_back({3 * j + 1, y & b[i]});
      if ((y & ~b[i]) > 0)
        dpp[i].push_back({3 * j + 2, y & ~b[i]});
    }
  }

  // repn(i, M)for(auto x:dp[i]) { cout << i << " " << x.first << " " <<
  // x.second << endl; }

  ll ans = 0;

  for (auto y : dpp[M]) {
    ll i = y.first;

    vll c(M + 1);
    ll x = i;
    repn(j, M) {
      c[M + 1 - j] = x % 3;
      x /= 3;
    }

    ll hou = 0;
    repn(j, M) {
      ll t = (S >> (j - 1)) & 1;
      ll u = (T >> (j - 1)) & 1;
      if (t == 0 && u == 1) {
        if (c[j] > 0 && hou >= 0) {
          hou++;
        }
      }
      if (t == 0 && u == 0) {
        if (c[j] != 2) {
          hou = -1;
        }
      }
      if (t == 1 && u == 1) {
        if (c[j] != 1) {
          hou = -1;
        }
      }
      if (t == 1 && u == 0) {
        cout << 0 << endl;
        return 0;
      }
    }

    if (hou == -1) {
      continue;
    }

    ll pop = 0;
    rep(j, N) {
      if ((y.second >> j) & 1) {
        pop++;
      }
    }

    ll cnt = 0;
    repn(j, min(K, pop)) { cnt += com[pop][j]; }

    // cout << i << " " << y.second << endl;
    // cout << hou << " " << cnt << endl << endl;

    if (hou % 2 == 0) {
      ans += cnt;
    } else {
      ans -= cnt;
    }
  }

  cout << ans << endl;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#define _USE_MATH_DEFINES
#include <complex>
#include <functional>
#include <math.h>
using namespace std;

#define rep(i, x) for (ll i = 0; i < x; i++)
#define repn(i, x) for (ll i = 1; i <= x; i++)

typedef long long ll;
const ll INF = 1e18 + 1e18;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
  if (a > b) {
    return a;
  }
  return b;
}

ll min(ll a, ll b) {
  if (a > b) {
    return b;
  }
  return a;
}

ll gcd(ll a, ll b) {
  if (b == 0) {
    return a;
  }
  if (a < b) {
    return gcd(b, a);
  }
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

struct edge {
  ll ind;
  ll fr;
  ll to;
  ll d;
};

class mint {
  long long x;

public:
  mint(long long x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  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) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint &a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint &a) const {
    mint res(*this);
    return res *= a;
  }

  mint pow(ll t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime MOD
  mint inv() const { return pow(MOD - 2); }
  mint &operator/=(const mint &a) { return (*this) *= a.inv(); }
  mint operator/(const mint &a) const {
    mint res(*this);
    return res /= a;
  }

  friend ostream &operator<<(ostream &os, const mint &m) {
    os << m.x;
    return os;
  }
};

mint pw(mint a, ll b) {
  if (b == 0) {
    return 1;
  }
  mint ret = pw(a, b >> 1);
  ret *= ret;
  if (b & 1) {
    ret *= a;
  }
  return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

//////////////////////////////////////

int main() {
  vvll com(60, vll(60, 0));
  com[0][0] = 1;
  rep(i, 60) rep(j, 60) {
    if (i > 0)
      com[i][j] += com[i - 1][j];
    if (i > 0 && j > 0) {
      com[i][j] += com[i - 1][j - 1];
    }
  }

  ll N, K, S, T;
  cin >> N >> K >> S >> T;
  vll A(N, 0);
  rep(i, N) cin >> A[i];

  ll M = 18;
  vll b(M + 1, 0);

  rep(i, N) repn(j, M) {
    if ((A[i] >> (j - 1)) & 1) {
      b[j] += 1 << i;
    }
  }

  // repn(j, M)cout << b[j] << endl;

  vector<map<ll, ll>> dp(M + 1);
  dp[0][0] = (1 << N) - 1;

  repn(i, M) {

    for (auto x : dp[i - 1]) {
      ll j = x.first;
      if (dp[i - 1][j] > 0)
        dp[i][3 * j] = dp[i - 1][j];
      if ((dp[i - 1][j] & b[i]) > 0)
        dp[i][3 * j + 1] = dp[i - 1][j] & b[i];
      if ((dp[i - 1][j] & ~b[i]) > 0)
        dp[i][3 * j + 2] = dp[i - 1][j] & ~b[i];
    }
  }

  // repn(i, M)for(auto x:dp[i]) { cout << i << " " << x.first << " " <<
  // x.second << endl; }

  ll ans = 0;

  for (auto y : dp[M]) {
    ll i = y.first;

    // cout << i << " " << dp[M][i] << endl;

    vll c(M + 1);
    ll x = i;
    repn(j, M) {
      c[M + 1 - j] = x % 3;
      x /= 3;
    }

    ll hou = 0;
    repn(j, M) {
      ll x = (S >> (j - 1)) & 1;
      ll y = (T >> (j - 1)) & 1;
      if (x == 0 && y == 1) {
        if (c[j] > 0 && hou >= 0) {
          hou++;
        }
      }
      if (x == 0 && y == 0) {
        if (c[j] != 2) {
          hou = -1;
        }
      }
      if (x == 1 && y == 1) {
        if (c[j] != 1) {
          hou = -1;
        }
      }
      if (x == 1 && y == 0) {
        cout << 0 << endl;
        return 0;
      }
    }

    if (hou == -1) {
      continue;
    }
    hou %= 2;

    ll pop = 0;
    rep(j, N) {
      if ((dp[M][i] >> j) & 1) {
        pop++;
      }
    }

    ll cnt = 0;
    rep(j, min(K, pop) + 1) { cnt += com[pop][j]; }

    // cout << hou << " " << cnt << endl << endl;

    if (hou % 2 == 0) {
      ans += cnt;
    } else {
      ans -= cnt;
    }
  }

  cout << ans << endl;
}