Problem p02661 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define ALL(obj) (obj).begin(), (obj).end()
#define SPEED                                                                  \\
  cin.tie(0);                                                                  \\
  ios::sync_with_stdio(false);

template <class T> using PQ = priority_queue<T>;
template <class T> using PQR = priority_queue<T, vector<T>, greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433L;

template <class T> vector<T> multivector(size_t N, T init) {
  return vector<T>(N, init);
}
template <class... T> auto multivector(size_t N, T... t) {
  return vector<decltype(multivector(t...))>(N, multivector(t...));
}
template <class T> void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    exit(0);
  }
}
template <class T, class U>
ostream &operator<<(ostream &o, const map<T, U> &obj) {
  o << "{";
  for (auto &x : obj)
    o << " {" << x.first << " : " << x.second << "}"
      << ",";
  o << " }";
  return o;
}
template <class T> ostream &operator<<(ostream &o, const set<T> &obj) {
  o << "{";
  for (auto itr = obj.begin(); itr != obj.end(); ++itr)
    o << (itr != obj.begin() ? ", " : "") << *itr;
  o << "}";
  return o;
}
template <class T> ostream &operator<<(ostream &o, const multiset<T> &obj) {
  o << "{";
  for (auto itr = obj.begin(); itr != obj.end(); ++itr)
    o << (itr != obj.begin() ? ", " : "") << *itr;
  o << "}";
  return o;
}
template <class T> ostream &operator<<(ostream &o, const vector<T> &obj) {
  o << "{";
  for (int i = 0; i < (int)obj.size(); ++i)
    o << (i > 0 ? ", " : "") << obj[i];
  o << "}";
  return o;
}
template <class T, class U>
ostream &operator<<(ostream &o, const pair<T, U> &obj) {
  o << "{" << obj.first << ", " << obj.second << "}";
  return o;
}
template <template <class tmp> class T, class U>
ostream &operator<<(ostream &o, const T<U> &obj) {
  o << "{";
  for (auto itr = obj.begin(); itr != obj.end(); ++itr)
    o << (itr != obj.begin() ? ", " : "") << *itr;
  o << "}";
  return o;
}
void print(void) { cout << endl; }
template <class Head> void print(Head &&head) {
  cout << head;
  print();
}
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head << " ";
  print(forward<Tail>(tail)...);
}
template <class T> void chmax(T &a, const T b) { a = max(a, b); }
template <class T> void chmin(T &a, const T b) { a = min(a, b); }
void YN(bool flg) { cout << (flg ? "YES" : "NO") << endl; }
void Yn(bool flg) { cout << (flg ? "Yes" : "No") << endl; }
void yn(bool flg) { cout << (flg ? "yes" : "no") << endl; }

ll f(ll N, vector<ll> L, vector<ll> R) {
  ll d, u;
  {
    ll ok = 0, ng = 1e9 + 1, md;
    while (ng - ok > 1) {
      md = (ok + ng) / 2;
      int cnt = 0;
      for (int i = 0; i < N; ++i)
        if (md <= R[i])
          cnt++;
      (cnt >= N / 2 + 1 ? ok : ng) = md;
    }
    d = ok;
  }
  {
    ll ok = 1e9 + 1, ng = 0, md;
    while (ok - ng > 1) {
      md = (ok + ng) / 2;
      int cnt = 0;
      for (int i = 0; i < N; ++i)
        if (L[i] <= md)
          cnt++;
      (cnt >= N / 2 + 1 ? ok : ng) = md;
    }
    u = ok;
  }
  return d - u + 1;
}

ll g(ll N, vector<ll> L, vector<ll> R) {
  sort(ALL(L));
  sort(ALL(R));
  double d = L[N / 2 - 1] + L[N / 2];
  double u = R[N / 2 - 1] + R[N / 2];
  d /= 2;
  u /= 2;
  u -= d;
  u += 0.5;
  return 2 * u;
}

int main() {
  ll N;
  cin >> N;
  vector<ll> L(N), R(N);
  for (int i = 0; i < N; ++i)
    cin >> L[i] >> R[i];
  if (N % 2 == 1) {
    cout << f(N, L, R) << endl;
  } else {
    cout << g(N, L, R) << endl;
  }
  return 0;
}


Error: -6
58122d71-7d0e-4199-bfe4-588b3c5410b5.out: /home/alex/Documents/bug-detection/input/Project_CodeNet/data/p02661/C++/s399463071.cpp:68: int main(): Assertion `false' failed.


Fixed submission:

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define ALL(obj) (obj).begin(), (obj).end()
#define SPEED                                                                  \\
  cin.tie(0);                                                                  \\
  ios::sync_with_stdio(false);

template <class T> using PQ = priority_queue<T>;
template <class T> using PQR = priority_queue<T, vector<T>, greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433L;

template <class T> vector<T> multivector(size_t N, T init) {
  return vector<T>(N, init);
}
template <class... T> auto multivector(size_t N, T... t) {
  return vector<decltype(multivector(t...))>(N, multivector(t...));
}
template <class T> void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    exit(0);
  }
}
template <class T, class U>
ostream &operator<<(ostream &o, const map<T, U> &obj) {
  o << "{";
  for (auto &x : obj)
    o << " {" << x.first << " : " << x.second << "}"
      << ",";
  o << " }";
  return o;
}
template <class T> ostream &operator<<(ostream &o, const set<T> &obj) {
  o << "{";
  for (auto itr = obj.begin(); itr != obj.end(); ++itr)
    o << (itr != obj.begin() ? ", " : "") << *itr;
  o << "}";
  return o;
}
template <class T> ostream &operator<<(ostream &o, const multiset<T> &obj) {
  o << "{";
  for (auto itr = obj.begin(); itr != obj.end(); ++itr)
    o << (itr != obj.begin() ? ", " : "") << *itr;
  o << "}";
  return o;
}
template <class T> ostream &operator<<(ostream &o, const vector<T> &obj) {
  o << "{";
  for (int i = 0; i < (int)obj.size(); ++i)
    o << (i > 0 ? ", " : "") << obj[i];
  o << "}";
  return o;
}
template <class T, class U>
ostream &operator<<(ostream &o, const pair<T, U> &obj) {
  o << "{" << obj.first << ", " << obj.second << "}";
  return o;
}
template <template <class tmp> class T, class U>
ostream &operator<<(ostream &o, const T<U> &obj) {
  o << "{";
  for (auto itr = obj.begin(); itr != obj.end(); ++itr)
    o << (itr != obj.begin() ? ", " : "") << *itr;
  o << "}";
  return o;
}
void print(void) { cout << endl; }
template <class Head> void print(Head &&head) {
  cout << head;
  print();
}
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head << " ";
  print(forward<Tail>(tail)...);
}
template <class T> void chmax(T &a, const T b) { a = max(a, b); }
template <class T> void chmin(T &a, const T b) { a = min(a, b); }
void YN(bool flg) { cout << (flg ? "YES" : "NO") << endl; }
void Yn(bool flg) { cout << (flg ? "Yes" : "No") << endl; }
void yn(bool flg) { cout << (flg ? "yes" : "no") << endl; }

ll f(ll N, vector<ll> L, vector<ll> R) {
  ll d, u;
  {
    ll ok = 0, ng = 1e9 + 1, md;
    while (ng - ok > 1) {
      md = (ok + ng) / 2;
      int cnt = 0;
      for (int i = 0; i < N; ++i)
        if (md <= R[i])
          cnt++;
      (cnt >= N / 2 + 1 ? ok : ng) = md;
    }
    d = ok;
  }
  {
    ll ok = 1e9 + 1, ng = 0, md;
    while (ok - ng > 1) {
      md = (ok + ng) / 2;
      int cnt = 0;
      for (int i = 0; i < N; ++i)
        if (L[i] <= md)
          cnt++;
      (cnt >= N / 2 + 1 ? ok : ng) = md;
    }
    u = ok;
  }
  return d - u + 1;
}

int main() {
  ll N;
  cin >> N;
  vector<ll> L(N), R(N);
  for (int i = 0; i < N; ++i)
    cin >> L[i] >> R[i];
  if (N % 2 == 1) {
    cout << f(N, L, R) << endl;
  } else {
    assert(false);
  }
  return 0;
}