Problem p03191 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdint>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
#define MP make_pair
#define PB push_back
#define inf 1000000007
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(x) (x).begin(), (x).end()

template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
  std::fill((T *)array, (T *)(array + N), val);
}

template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

template <unsigned int mod> class ModInt {
private:
  unsigned int v;
  static unsigned int norm(const unsigned int &x) {
    return x < mod ? x : x - mod;
  }
  static ModInt make(const unsigned int &x) {
    ModInt m;
    return m.v = x, m;
  }
  static ModInt inv(const ModInt &x) { return make(inverse(x.v, mod)); }
  static unsigned int inverse(int a, int m) {
    int u[] = {a, 1, 0}, v[] = {m, 0, 1}, t;
    while (*v) {
      t = *u / *v;
      swap(u[0] -= t * v[0], v[0]), swap(u[1] -= t * v[1], v[1]),
          swap(u[2] -= t * v[2], v[2]);
    }
    return (u[1] % m + m) % m;
  }

public:
  ModInt() : v{0} {}
  ModInt(const long long val) : v{norm(val % mod + mod)} {}
  ModInt(const ModInt<mod> &n) : v{n()} {}
  explicit operator bool() const noexcept { return v != 0; }
  bool operator!() const noexcept { return !static_cast<bool>(*this); }
  ModInt &operator=(const ModInt &n) { return v = n(), (*this); }
  ModInt &operator=(const long long val) {
    return v = norm(val % mod + mod), (*this);
  }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { return v == 0 ? make(0) : make(mod - v); }
  ModInt operator+(const ModInt &val) const { return make(norm(v + val())); }
  ModInt operator-(const ModInt &val) const {
    return make(norm(v + mod - val()));
  }
  ModInt operator*(const ModInt &val) const {
    return make((long long)v * val() % mod);
  }
  ModInt operator/(const ModInt &val) const { return *this * inv(val); }
  ModInt &operator+=(const ModInt &val) { return *this = *this + val; }
  ModInt &operator-=(const ModInt &val) { return *this = *this - val; }
  ModInt &operator*=(const ModInt &val) { return *this = *this * val; }
  ModInt &operator/=(const ModInt &val) { return *this = *this / val; }
  ModInt operator+(const long long val) const { return ModInt{v + val}; }
  ModInt operator-(const long long val) const { return ModInt{v - val}; }
  ModInt operator*(const long long val) const {
    return ModInt{(long long)v * (val % mod)};
  }
  ModInt operator/(const long long val) const {
    return ModInt{(long long)v * inv(val)};
  }
  ModInt &operator+=(const long long val) { return *this = *this + val; }
  ModInt &operator-=(const long long val) { return *this = *this - val; }
  ModInt &operator*=(const long long val) { return *this = *this * val; }
  ModInt &operator/=(const long long val) { return *this = *this / val; }
  bool operator==(const ModInt &val) const { return v == val.v; }
  bool operator!=(const ModInt &val) const { return !(*this == val); }
  bool operator==(const long long val) const {
    return v == norm(val % mod + mod);
  }
  bool operator!=(const long long val) const { return !(*this == val); }
  unsigned int operator()() const { return v; }
  friend ModInt operator+(const long long val, const ModInt &n) {
    return n + val;
  }
  friend ModInt operator-(const long long val, const ModInt &n) {
    return ModInt{val - n()};
  }
  friend ModInt operator*(const long long val, const ModInt &n) {
    return n * val;
  }
  friend ModInt operator/(const long long val, const ModInt &n) {
    return ModInt{val} / n;
  }
  friend bool operator==(const long long val, const ModInt &n) {
    return n == val;
  }
  friend bool operator!=(const long long val, const ModInt &n) {
    return !(val == n);
  }
  friend istream &operator>>(istream &is, ModInt &n) {
    unsigned int v;
    return is >> v, n = v, is;
  }
  friend ostream &operator<<(ostream &os, const ModInt &n) {
    return (os << n());
  }
  friend ModInt mod_pow(ModInt x, long long n) {
    ModInt ans = 1;
    while (n) {
      if (n & 1)
        ans *= x;
      x *= x, n >>= 1;
    }
    return ans;
  }
};

#define MOD 1000000007
using mod = ModInt<MOD>;

#define MAX_N 200000
mod inv[MAX_N], fac[MAX_N], finv[MAX_N];

void make() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX_N; i++) {
    inv[i] = MOD - inv[MOD % i] * (MOD / i);
    fac[i] = fac[i - 1] * i;
    finv[i] = finv[i - 1] * inv[i];
  }
}

mod comb(int a, int b) {
  if (a < b)
    return 0;
  return fac[a] * finv[b] * finv[a - b];
}

mod dp[303][303][303];
int cc[303];
int main() {
  make();
  int n;
  cin >> n;
  vector<int> a(2 * n);
  rep(i, 2 * n) cin >> a[i];
  vector<bool> p(2 * n + 1);
  p[0] = 1;
  vector<int> b;
  rep(i, n) {
    if (a[2 * i] != -1 && a[2 * i + 1] != -1) {
      p[a[2 * i]] = 1;
      p[a[2 * i + 1]] = 1;
    } else {
      b.push_back(a[2 * i]);
      b.push_back(a[2 * i + 1]);
    }
  }
  map<int, int> mp;
  mp[-1] = -1;
  int c = 1;
  rep(i, 2 * n + 1) {
    if (!p[i]) {
      mp[i] = c;
      c++;
    }
  }
  int m = b.size();
  m /= 2;
  rep(i, m) {
    b[2 * i] = mp[b[2 * i]];
    b[2 * i + 1] = mp[b[2 * i + 1]];
  }
  set<int> st;
  int T = 0;
  rep(i, m) {
    cerr << b[2 * i] << " " << b[2 * i + 1] << endl;
    if (b[2 * i] == -1 && b[2 * i + 1] == -1) {
      T++;
    } else {
      st.insert(max(b[2 * i], b[2 * i + 1]));
      cc[max(b[2 * i], b[2 * i + 1])]++;
    }
  }
  for (int i = 0; i < 2 * m; i++) {
    cc[i + 1] += cc[i];
  }
  dp[2 * m][0][T] = 1;
  for (int k = 2 * m; k >= 1; k--) {
    for (int s = 0; s <= 2 * m; s++) {
      for (int t = 0; t <= T; t++) {
        int u = s + 2 * t + 2 * cc[k] - k;
        if (u < 0)
          continue;
        if (st.count(k)) {
          dp[k - 1][s + 1][t] += dp[k][s][t];
          dp[k - 1][s][t] += dp[k][s][t];
        } else {
          dp[k - 1][s][t] += dp[k][s][t];
          if (t != 0)
            dp[k - 1][s][t - 1] += dp[k][s][t];
          // if(t!=0) dp[k-1][s+1][t-1] += dp[k][s][t];
          if (s != 0)
            dp[k - 1][s - 1][t] += dp[k][s][t] * s;
        }
      }
    }
  }
  cout << dp[0][0][0] * fac[T] << endl;
  return 0;
}

Fixed submission:
#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdint>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
#define MP make_pair
#define PB push_back
#define inf 1000000007
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(x) (x).begin(), (x).end()

template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
  std::fill((T *)array, (T *)(array + N), val);
}

template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

template <unsigned int mod> class ModInt {
private:
  unsigned int v;
  static unsigned int norm(const unsigned int &x) {
    return x < mod ? x : x - mod;
  }
  static ModInt make(const unsigned int &x) {
    ModInt m;
    return m.v = x, m;
  }
  static ModInt inv(const ModInt &x) { return make(inverse(x.v, mod)); }
  static unsigned int inverse(int a, int m) {
    int u[] = {a, 1, 0}, v[] = {m, 0, 1}, t;
    while (*v) {
      t = *u / *v;
      swap(u[0] -= t * v[0], v[0]), swap(u[1] -= t * v[1], v[1]),
          swap(u[2] -= t * v[2], v[2]);
    }
    return (u[1] % m + m) % m;
  }

public:
  ModInt() : v{0} {}
  ModInt(const long long val) : v{norm(val % mod + mod)} {}
  ModInt(const ModInt<mod> &n) : v{n()} {}
  explicit operator bool() const noexcept { return v != 0; }
  bool operator!() const noexcept { return !static_cast<bool>(*this); }
  ModInt &operator=(const ModInt &n) { return v = n(), (*this); }
  ModInt &operator=(const long long val) {
    return v = norm(val % mod + mod), (*this);
  }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { return v == 0 ? make(0) : make(mod - v); }
  ModInt operator+(const ModInt &val) const { return make(norm(v + val())); }
  ModInt operator-(const ModInt &val) const {
    return make(norm(v + mod - val()));
  }
  ModInt operator*(const ModInt &val) const {
    return make((long long)v * val() % mod);
  }
  ModInt operator/(const ModInt &val) const { return *this * inv(val); }
  ModInt &operator+=(const ModInt &val) { return *this = *this + val; }
  ModInt &operator-=(const ModInt &val) { return *this = *this - val; }
  ModInt &operator*=(const ModInt &val) { return *this = *this * val; }
  ModInt &operator/=(const ModInt &val) { return *this = *this / val; }
  ModInt operator+(const long long val) const { return ModInt{v + val}; }
  ModInt operator-(const long long val) const { return ModInt{v - val}; }
  ModInt operator*(const long long val) const {
    return ModInt{(long long)v * (val % mod)};
  }
  ModInt operator/(const long long val) const {
    return ModInt{(long long)v * inv(val)};
  }
  ModInt &operator+=(const long long val) { return *this = *this + val; }
  ModInt &operator-=(const long long val) { return *this = *this - val; }
  ModInt &operator*=(const long long val) { return *this = *this * val; }
  ModInt &operator/=(const long long val) { return *this = *this / val; }
  bool operator==(const ModInt &val) const { return v == val.v; }
  bool operator!=(const ModInt &val) const { return !(*this == val); }
  bool operator==(const long long val) const {
    return v == norm(val % mod + mod);
  }
  bool operator!=(const long long val) const { return !(*this == val); }
  unsigned int operator()() const { return v; }
  friend ModInt operator+(const long long val, const ModInt &n) {
    return n + val;
  }
  friend ModInt operator-(const long long val, const ModInt &n) {
    return ModInt{val - n()};
  }
  friend ModInt operator*(const long long val, const ModInt &n) {
    return n * val;
  }
  friend ModInt operator/(const long long val, const ModInt &n) {
    return ModInt{val} / n;
  }
  friend bool operator==(const long long val, const ModInt &n) {
    return n == val;
  }
  friend bool operator!=(const long long val, const ModInt &n) {
    return !(val == n);
  }
  friend istream &operator>>(istream &is, ModInt &n) {
    unsigned int v;
    return is >> v, n = v, is;
  }
  friend ostream &operator<<(ostream &os, const ModInt &n) {
    return (os << n());
  }
  friend ModInt mod_pow(ModInt x, long long n) {
    ModInt ans = 1;
    while (n) {
      if (n & 1)
        ans *= x;
      x *= x, n >>= 1;
    }
    return ans;
  }
};

#define MOD 1000000007
using mod = ModInt<MOD>;

#define MAX_N 200000
mod inv[MAX_N], fac[MAX_N], finv[MAX_N];

void make() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX_N; i++) {
    inv[i] = MOD - inv[MOD % i] * (MOD / i);
    fac[i] = fac[i - 1] * i;
    finv[i] = finv[i - 1] * inv[i];
  }
}

mod comb(int a, int b) {
  if (a < b)
    return 0;
  return fac[a] * finv[b] * finv[a - b];
}

mod dp[603][603][603];
int cc[603];
int main() {
  make();
  int n;
  cin >> n;
  vector<int> a(2 * n);
  rep(i, 2 * n) cin >> a[i];
  vector<bool> p(2 * n + 1);
  p[0] = 1;
  vector<int> b;
  rep(i, n) {
    if (a[2 * i] != -1 && a[2 * i + 1] != -1) {
      p[a[2 * i]] = 1;
      p[a[2 * i + 1]] = 1;
    } else {
      b.push_back(a[2 * i]);
      b.push_back(a[2 * i + 1]);
    }
  }
  map<int, int> mp;
  mp[-1] = -1;
  int c = 1;
  rep(i, 2 * n + 1) {
    if (!p[i]) {
      mp[i] = c;
      c++;
    }
  }
  int m = b.size();
  m /= 2;
  rep(i, m) {
    b[2 * i] = mp[b[2 * i]];
    b[2 * i + 1] = mp[b[2 * i + 1]];
  }
  set<int> st;
  int T = 0;
  rep(i, m) {
    cerr << b[2 * i] << " " << b[2 * i + 1] << endl;
    if (b[2 * i] == -1 && b[2 * i + 1] == -1) {
      T++;
    } else {
      st.insert(max(b[2 * i], b[2 * i + 1]));
      cc[max(b[2 * i], b[2 * i + 1])]++;
    }
  }
  for (int i = 0; i < 2 * m; i++) {
    cc[i + 1] += cc[i];
  }
  dp[2 * m][0][T] = 1;
  for (int k = 2 * m; k >= 1; k--) {
    for (int s = 0; s <= 2 * m; s++) {
      for (int t = 0; t <= T; t++) {
        int u = s + 2 * t + 2 * cc[k] - k;
        if (u < 0)
          continue;
        if (st.count(k)) {
          dp[k - 1][s + 1][t] += dp[k][s][t];
          dp[k - 1][s][t] += dp[k][s][t];
        } else {
          dp[k - 1][s][t] += dp[k][s][t];
          if (t != 0)
            dp[k - 1][s][t - 1] += dp[k][s][t];
          // if(t!=0) dp[k-1][s+1][t-1] += dp[k][s][t];
          if (s != 0)
            dp[k - 1][s - 1][t] += dp[k][s][t] * s;
        }
      }
    }
  }
  cout << dp[0][0][0] * fac[T] << endl;
  return 0;
}