Problem p03174 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;

using VS = vector<string>;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using PLL = pair<LL, LL>;
using VL = vector<LL>;
using VVL = vector<VL>;

#define ALL(a) begin((a)), end((a))
#define RALL(a) (a).rbegin(), (a).rend()
#define SZ(a) int((a).size())
#define SORT(c) sort(ALL((c)))
#define RSORT(c) sort(RALL((c)))
#define UNIQ(c) (c).erase(unique(ALL((c))), end((c)))
#define FOR(i, s, e) for (int(i) = (s); (i) < (e); (i)++)
#define FORR(i, s, e) for (int(i) = (s); (i) > (e); (i)--)
// #pragma GCC optimize ("-O3")
#ifdef YANG33
#include "mydebug.hpp"
#else
#define DD(x)
#endif
const int INF = 1e9;
const LL LINF = 1e16;
const LL MOD = 1000000007;
const double PI = acos(-1.0);
int DX[8] = {0, 0, 1, -1, 1, 1, -1, -1};
int DY[8] = {1, -1, 0, 0, 1, -1, 1, -1};

/* -----  2019/01/06  Problem: EDU_DP O / Link: __CONTEST_URL__  ----- */
/* ------問題------



-----問題ここまで----- */
/* -----解説等-----

permanentを160人も通せるわけが無いので

----解説ここまで---- */

template <::std::uint_fast32_t MODULO> class modint {
public:
  using uint32 = ::std::uint_fast32_t;
  using uint64 = ::std::uint_fast64_t;
  using value_type = uint32;
  uint32 a;
  modint() noexcept : a(0) {}
  modint(const uint32 x) noexcept : a(x) {}
  modint operator+(const modint &o) const noexcept {
    return a + o.a < MODULO ? modint(a + o.a) : modint(a + o.a - MODULO);
  }
  modint operator-(const modint &o) const noexcept {
    return modint(a < o.a ? a + MODULO - o.a : a - o.a);
  }
  modint operator*(const modint &o) const noexcept {
    return modint(static_cast<uint64>(a) * o.a % MODULO);
  }
  modint operator/(const modint &o) const {
    return modint(static_cast<uint64>(a) * (~o).a % MODULO);
  }
  modint &operator+=(const modint &o) noexcept { return *this = *this + o; }
  modint &operator-=(const modint &o) noexcept { return *this = *this - o; }
  modint &operator*=(const modint &o) noexcept { return *this = *this * o; }
  modint &operator/=(const modint &o) { return *this = *this / o; }
  modint operator~() const noexcept { return pow(MODULO - 2); }
  modint operator-() const noexcept { return a ? modint(MODULO - a) : *this; }
  modint operator++() noexcept { return a == MODULO - 1 ? a = 0 : ++a, *this; }
  modint operator--() noexcept { return a ? --a : a = MODULO - 1, *this; }
  bool operator==(const modint &o) const noexcept { return a == o.a; }
  bool operator!=(const modint &o) const noexcept { return a != o.a; }
  bool operator<(const modint &o) const noexcept { return a < o.a; }
  bool operator<=(const modint &o) const noexcept { return a <= o.a; }
  bool operator>(const modint &o) const noexcept { return a > o.a; }
  bool operator>=(const modint &o) const noexcept { return a >= o.a; }
  explicit operator bool() const noexcept { return a; }
  explicit operator uint32() const noexcept { return a; }
  modint pow(uint32 x) const noexcept {
    uint64 t = a, u = 1;
    while (x) {
      if (x & 1)
        u = u * t % MODULO;
      t = (t * t) % MODULO;
      x >>= 1;
    }
    return modint(u);
  }
  uint32 get() const noexcept { return a; }
};
using mint = modint<MOD>;
void chmax(LL &a, LL b) { a = max(a, b); }
void chmin(LL &a, LL b) { a = min(a, b); }

mint dp[22][1 << 22];
int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  int N;
  cin >> N;
  VVI a(N, VI(N));
  FOR(i, 0, N) {
    FOR(j, 0, N) { cin >> a[i][j]; }
  }

  dp[0][0] = 1;
  FOR(i, 0, N) {
    FOR(state, 0, 1 << N) {
      FOR(j, 0, N) {
        if (state & 1 << j)
          continue;
        if (a[i][j]) {
          dp[i + 1][state | (1 << j)] += dp[i][state];
        }
      }
    }
  }
  cout << dp[N][(1 << N) - 1].get() << endl;
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;

using VS = vector<string>;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using PLL = pair<LL, LL>;
using VL = vector<LL>;
using VVL = vector<VL>;

#define ALL(a) begin((a)), end((a))
#define RALL(a) (a).rbegin(), (a).rend()
#define SZ(a) int((a).size())
#define SORT(c) sort(ALL((c)))
#define RSORT(c) sort(RALL((c)))
#define UNIQ(c) (c).erase(unique(ALL((c))), end((c)))
#define FOR(i, s, e) for (int(i) = (s); (i) < (e); (i)++)
#define FORR(i, s, e) for (int(i) = (s); (i) > (e); (i)--)
// #pragma GCC optimize ("-O3")
#ifdef YANG33
#include "mydebug.hpp"
#else
#define DD(x)
#endif
const int INF = 1e9;
const LL LINF = 1e16;
const LL MOD = 1000000007;
const double PI = acos(-1.0);
int DX[8] = {0, 0, 1, -1, 1, 1, -1, -1};
int DY[8] = {1, -1, 0, 0, 1, -1, 1, -1};

/* -----  2019/01/06  Problem: EDU_DP O / Link: __CONTEST_URL__  ----- */
/* ------問題------



-----問題ここまで----- */
/* -----解説等-----

permanentを160人も通せるわけが無いので

----解説ここまで---- */

template <::std::uint_fast32_t MODULO> class modint {
public:
  using uint32 = ::std::uint_fast32_t;
  using uint64 = ::std::uint_fast64_t;
  using value_type = uint32;
  uint32 a;
  modint() noexcept : a(0) {}
  modint(const uint32 x) noexcept : a(x) {}
  modint operator+(const modint &o) const noexcept {
    return a + o.a < MODULO ? modint(a + o.a) : modint(a + o.a - MODULO);
  }
  modint operator-(const modint &o) const noexcept {
    return modint(a < o.a ? a + MODULO - o.a : a - o.a);
  }
  modint operator*(const modint &o) const noexcept {
    return modint(static_cast<uint64>(a) * o.a % MODULO);
  }
  modint operator/(const modint &o) const {
    return modint(static_cast<uint64>(a) * (~o).a % MODULO);
  }
  modint &operator+=(const modint &o) noexcept { return *this = *this + o; }
  modint &operator-=(const modint &o) noexcept { return *this = *this - o; }
  modint &operator*=(const modint &o) noexcept { return *this = *this * o; }
  modint &operator/=(const modint &o) { return *this = *this / o; }
  modint operator~() const noexcept { return pow(MODULO - 2); }
  modint operator-() const noexcept { return a ? modint(MODULO - a) : *this; }
  modint operator++() noexcept { return a == MODULO - 1 ? a = 0 : ++a, *this; }
  modint operator--() noexcept { return a ? --a : a = MODULO - 1, *this; }
  bool operator==(const modint &o) const noexcept { return a == o.a; }
  bool operator!=(const modint &o) const noexcept { return a != o.a; }
  bool operator<(const modint &o) const noexcept { return a < o.a; }
  bool operator<=(const modint &o) const noexcept { return a <= o.a; }
  bool operator>(const modint &o) const noexcept { return a > o.a; }
  bool operator>=(const modint &o) const noexcept { return a >= o.a; }
  explicit operator bool() const noexcept { return a; }
  explicit operator uint32() const noexcept { return a; }
  modint pow(uint32 x) const noexcept {
    uint64 t = a, u = 1;
    while (x) {
      if (x & 1)
        u = u * t % MODULO;
      t = (t * t) % MODULO;
      x >>= 1;
    }
    return modint(u);
  }
  uint32 get() const noexcept { return a; }
};
using mint = modint<MOD>;
void chmax(LL &a, LL b) { a = max(a, b); }
void chmin(LL &a, LL b) { a = min(a, b); }

mint dp[22][1 << 22];
int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  int N;
  cin >> N;
  VVI a(N, VI(N));
  FOR(i, 0, N) {
    FOR(j, 0, N) { cin >> a[i][j]; }
  }

  dp[0][0] = 1;
  FOR(i, 0, N) {
    FOR(j, 0, N) {
      if (a[i][j]) {
        FOR(state, 0, 1 << N) {
          if (state & 1 << j)
            continue;
          dp[i + 1][state | (1 << j)] += dp[i][state];
        }
      }
    }
  }
  cout << dp[N][(1 << N) - 1].get() << endl;
  return 0;
}