Problem p02616 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
using Real = long double;
using Point = complex<Real>; // Point and Vector2d is the same!
using Vector2d = complex<Real>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
const double EPS = 1e-15;
const double PI = 3.14159265358979323846;
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
istream &operator>>(istream &is, Point &p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \\
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \\
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \\
          << "    ",                                                           \\
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

template <int MOD> struct Fp {
  long long val;
  constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
    if (val < 0)
      val += MOD;
  }
  constexpr int getmod() { return MOD; }
  constexpr Fp operator-() const noexcept { return val ? MOD - val : 0; }
  constexpr Fp operator+(const Fp &r) const noexcept { return Fp(*this) += r; }
  constexpr Fp operator-(const Fp &r) const noexcept { return Fp(*this) -= r; }
  constexpr Fp operator*(const Fp &r) const noexcept { return Fp(*this) *= r; }
  constexpr Fp operator/(const Fp &r) const noexcept { return Fp(*this) /= r; }
  constexpr Fp &operator+=(const Fp &r) noexcept {
    val += r.val;
    if (val >= MOD)
      val -= MOD;
    return *this;
  }
  constexpr Fp &operator-=(const Fp &r) noexcept {
    val -= r.val;
    if (val < 0)
      val += MOD;
    return *this;
  }
  constexpr Fp &operator*=(const Fp &r) noexcept {
    val = val * r.val % MOD;
    return *this;
  }
  constexpr Fp &operator/=(const Fp &r) noexcept {
    long long a = r.val, b = MOD, u = 1, v = 0;
    while (b) {
      long long t = a / b;
      a -= t * b;
      swap(a, b);
      u -= t * v;
      swap(u, v);
    }
    val = val * u % MOD;
    if (val < 0)
      val += MOD;
    return *this;
  }
  constexpr bool operator==(const Fp &r) const noexcept {
    return this->val == r.val;
  }
  constexpr bool operator!=(const Fp &r) const noexcept {
    return this->val != r.val;
  }
  friend constexpr ostream &operator<<(ostream &os, const Fp<MOD> &x) noexcept {
    return os << x.val;
  }
  friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
    if (n == 0)
      return 1;
    auto t = modpow(a, n / 2);
    t = t * t;
    if (n & 1)
      t = t * a;
    return t;
  }
};
using mint = Fp<1000000007>;
signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, k;
  cin >> n >> k;
  vector<int> p, m;
  mint ans = 1;
  if (n == k) {
    for (int i = 0; i < n; i++) {
      int a;
      cin >> a;
      a += MOD;
      a %= MOD;
      ans *= (mint)a;
    }
    print(ans);
    return 0;
  }

  rep(i, n) {
    int a;
    cin >> a;
    if (a >= 0)
      p.pb(a);
    else
      m.pb(a);
  }
  if (p.size() == 0) {
    if (k % 2 == 0)
      sort(m.begin(), m.end());
    else
      sort(m.begin(), m.end(), greater<int>());
    rep(i, k) { ans *= (mint)m[i]; }
    print(ans);
    return 0;
  }
  sort(p.begin(), p.end(), greater<int>());
  sort(m.begin(), m.end());
  vector<vector<int>> daten(2, vector<int>());
  int x = 0, y = 0;
  for (int i = 0; i < k; i++) {
    if (x == p.size()) {

      daten[1].pb(-m[y++]);
    } else if (y == m.size()) {

      daten[0].pb(p[x++]);
    } else {
      if (p[x] >= -m[y]) {
        daten[0].pb(p[x++]);
      } else {
        daten[1].pb(-m[y++]);
      }
    }
  }

  if (daten[1].size() % 2) {
    dump(x, y, p.size(), m.size(), daten[0].size(), daten[1].size());
    // 負を出して非負をいれる or 非負を出して負をいれる
    if (x == p.size()) { // 非負を出して負をいれる
      daten[0][daten[0].size() - 1] = 1;
      daten[1].pb(-m[y++]);
    } else if (y == m.size()) { // 負を出して非負をいれる
      daten[1][daten[1].size() - 1] = 1;
      daten[0].pb(p[x++]);
    } else {
      if (daten[0].size() == 0) {
        daten[1][daten[1].size() - 1] = 1;
        daten[0].pb(p[x++]);
      } else if (daten[1].size() == 0) {
        daten[0][daten[0].size() - 1] = 1;
        daten[1].pb(-m[y++]);
      } else if (-m[y] * daten[1][daten[1].size() - 1] >
                 p[x] * daten[0][daten[0].size() - 1]) {
        daten[0][daten[0].size() - 1] = 1;
        daten[1].pb(-m[y++]);
      } else {
        daten[1][daten[1].size() - 1] = 1;
        daten[0].pb(p[x++]);
      }
    }
  }
  for (int i = 0; i < daten[0].size(); i++) {
    ans *= (mint)daten[0][i];
  }
  for (int i = 0; i < daten[1].size(); i++) {
    ans *= (mint)daten[1][i];
  }
  print(ans);
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
using Real = long double;
using Point = complex<Real>; // Point and Vector2d is the same!
using Vector2d = complex<Real>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
const double EPS = 1e-15;
const double PI = 3.14159265358979323846;
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
istream &operator>>(istream &is, Point &p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \\
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \\
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \\
          << "    ",                                                           \\
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

template <int MOD> struct Fp {
  long long val;
  constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
    if (val < 0)
      val += MOD;
  }
  constexpr int getmod() { return MOD; }
  constexpr Fp operator-() const noexcept { return val ? MOD - val : 0; }
  constexpr Fp operator+(const Fp &r) const noexcept { return Fp(*this) += r; }
  constexpr Fp operator-(const Fp &r) const noexcept { return Fp(*this) -= r; }
  constexpr Fp operator*(const Fp &r) const noexcept { return Fp(*this) *= r; }
  constexpr Fp operator/(const Fp &r) const noexcept { return Fp(*this) /= r; }
  constexpr Fp &operator+=(const Fp &r) noexcept {
    val += r.val;
    if (val >= MOD)
      val -= MOD;
    return *this;
  }
  constexpr Fp &operator-=(const Fp &r) noexcept {
    val -= r.val;
    if (val < 0)
      val += MOD;
    return *this;
  }
  constexpr Fp &operator*=(const Fp &r) noexcept {
    val = val * r.val % MOD;
    return *this;
  }
  constexpr Fp &operator/=(const Fp &r) noexcept {
    long long a = r.val, b = MOD, u = 1, v = 0;
    while (b) {
      long long t = a / b;
      a -= t * b;
      swap(a, b);
      u -= t * v;
      swap(u, v);
    }
    val = val * u % MOD;
    if (val < 0)
      val += MOD;
    return *this;
  }
  constexpr bool operator==(const Fp &r) const noexcept {
    return this->val == r.val;
  }
  constexpr bool operator!=(const Fp &r) const noexcept {
    return this->val != r.val;
  }
  friend constexpr ostream &operator<<(ostream &os, const Fp<MOD> &x) noexcept {
    return os << x.val;
  }
  friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
    if (n == 0)
      return 1;
    auto t = modpow(a, n / 2);
    t = t * t;
    if (n & 1)
      t = t * a;
    return t;
  }
};
using mint = Fp<1000000007>;
signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, k;
  cin >> n >> k;
  vector<int> p, m;
  mint ans = 1;
  if (n == k) {
    for (int i = 0; i < n; i++) {
      int a;
      cin >> a;
      a += MOD;
      a %= MOD;
      ans *= (mint)a;
    }
    print(ans);
    return 0;
  }

  rep(i, n) {
    int a;
    cin >> a;
    if (a >= 0)
      p.pb(a);
    else
      m.pb(a);
  }
  if (p.size() == 0) {
    rep(i, k) { ans *= (mint)m[i]; }
    print(ans);
    return 0;
  }
  sort(p.begin(), p.end(), greater<int>());
  sort(m.begin(), m.end());
  vector<vector<int>> daten(2, vector<int>());
  int x = 0, y = 0;
  for (int i = 0; i < k; i++) {
    if (x == p.size()) {
      daten[1].pb(m[y++]);
    } else if (y == m.size()) {
      daten[0].pb(p[x++]);
    } else {
      if (p[x] > -m[y]) {
        daten[0].pb(p[x++]);
      } else {
        daten[1].pb(m[y++]);
      }
    }
  }
  dump(daten);
  if (daten[1].size() % 2) {
    // 負を出して非負をいれる or 非負を出して負をいれる
    if (x == p.size()) { // 非負を出して負をいれる
      daten[0][daten[0].size() - 1] = 1;
      daten[1].pb(m[y++]);
    } else if (y == m.size()) { // 負を出して非負をいれる
      daten[1][daten[1].size() - 1] = 1;
      daten[0].pb(p[x++]);
    } else {
      if (-m[y] > p[x]) {
        daten[0][daten[0].size() - 1] = 1;
        daten[1].pb(m[y++]);
      } else {
        daten[1][daten[1].size() - 1] = 1;
        daten[0].pb(p[x++]);
      }
    }
  }
  for (int i = 0; i < daten[0].size(); i++) {
    ans *= (mint)daten[0][i];
  }
  for (int i = 0; i < daten[1].size(); i++) {
    ans *= (mint)daten[1][i];
  }
  print(ans);
}