Problem p02983 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <cmath>
#include <complex> // complex<double> a(1.2 , 2.3);// real(): 1.2, imag()2.3
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <vector>
using namespace std;

#define MOD 1000000007
#define ll long long
#define ld long double
#define FOR(i, a, b) for (ll i = (ll)a; i < (ll)b; i++)
#define rep(i, n) FOR(i, 0, n)
#define pb push_back
#define mp make_pair
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define rmsame(a) sort(all(a)), a.erase(unique(all(a)), a.end())
#define rmvector(a, b)                                                         \
  rep(i, a.size()) rep(j, b.size()) if (a[i] == b[j]) {                        \
    a.erase(a.begin() + i);                                                    \
    i--;                                                                       \
    break;                                                                     \
  }
#define first_more_idx(ve, num)                                                \
  upper_bound(all(ve), num) - ve.begin() // idx = first_more_idx(ve,num); if(idx
                                         // = ve.size()) , then not exist
#define first_lessequal_idx(ve, num) lower_bound(all(ve), num) - ve.begin()
#define pq_pair_tB                                                             \
  priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>
#define pq_pair_ts priority_queue<pair<ll, ll>> // only sort first param
template <typename X> bool exist(vector<X> vec, X item) {
  return find(all(vec), item) != vec.end();
}
ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
ll power(ll x, ll n) {
  if (n == 0)
    return 1;
  return (n % 2) ? x * power(x, n - 1) % MOD : power(x * x % MOD, n / 2);
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll L, R;
  cin >> L >> R;

  ll ans = 2019;
  for (ll i = L; i <= R; i++) {
    for (ll j = i + 1; j <= R; j++) {
      ans = min(ans, i * j % 2019);
    }
  }

  cout << ans << endl;
  // cout << fixed << setprecision(16) << ans << endl;
  return 0;
}


Fixed submission:
#include <algorithm>
#include <cmath>
#include <complex> // complex<double> a(1.2 , 2.3);// real(): 1.2, imag()2.3
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <vector>
using namespace std;

#define MOD 1000000007
#define ll long long
#define ld long double
#define FOR(i, a, b) for (ll i = (ll)a; i < (ll)b; i++)
#define rep(i, n) FOR(i, 0, n)
#define pb push_back
#define mp make_pair
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define rmsame(a) sort(all(a)), a.erase(unique(all(a)), a.end())
#define rmvector(a, b)                                                         \
  rep(i, a.size()) rep(j, b.size()) if (a[i] == b[j]) {                        \
    a.erase(a.begin() + i);                                                    \
    i--;                                                                       \
    break;                                                                     \
  }
#define first_more_idx(ve, num)                                                \
  upper_bound(all(ve), num) - ve.begin() // idx = first_more_idx(ve,num); if(idx
                                         // = ve.size()) , then not exist
#define first_lessequal_idx(ve, num) lower_bound(all(ve), num) - ve.begin()
#define pq_pair_tB                                                             \
  priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>
#define pq_pair_ts priority_queue<pair<ll, ll>> // only sort first param
template <typename X> bool exist(vector<X> vec, X item) {
  return find(all(vec), item) != vec.end();
}
ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
ll power(ll x, ll n) {
  if (n == 0)
    return 1;
  return (n % 2) ? x * power(x, n - 1) % MOD : power(x * x % MOD, n / 2);
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll L, R;
  cin >> L >> R;

  ll ans = 2019;
  for (ll i = L; i <= min(L + 2020, R); i++) {
    for (ll j = i + 1; j <= min(L + 2020, R); j++) {
      ans = min(ans, i * j % 2019);
    }
  }

  cout << ans << endl;
  // cout << fixed << setprecision(16) << ans << endl;
  return 0;
}