Problem p02983 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <array>
#include <bitset>
#include <cmath>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#define M_PI 3.141592653589793238
using namespace std;
long long p9 = 998244353;
long long p1 = 1000000007;
#define upperbound(v, val) upper_bound(v.begin(), v.end(), val) - v.begin()
#define lowerbound(v, val) lower_bound(v.begin(), v.end(), val) - v.begin()
#define int long long
#define vel vector<long long>
#define vvel vector<vel>
#define rep(i, n) for (int i = 0; i < n; i++)
#define sor(v) sort(v.begin(), v.end())
#define mmax(a, b) a = max(a, b)
#define mmin(a, b) a = min(a, b)
#define mkp(a, b) make_pair(a, b)
#define pin pair<int, int>
#define qin pair<pin, int>
#define V vector
#define Endl endl
#define veb vector<bool>
#define fcout cout << fixed << setprecision(15)
#define rev(s) reverse(s.begin(), s.end())
#define lower(h, val) (lower_bound(h.begin(), h.end(), val) - h.begin())
#define upper(h, val) (upper_bound(h.begin(), h.end(), val) - h.begin())
#define vveb V<veb>
#define omajinai                                                               \
  cin.tie(0);                                                                  \
  ios::sync_with_stdio(false);
#define endl "\n"
#define pb push_back
vel kai;
vel inv_kai;
vel inv;
int root(int x, vel &pa) {
  if (pa[x] == -1) {
    return x;
  }
  int ans = root(pa[x], pa);
  pa[x] = ans;
  return ans;
}
bool mar(int x, int y, vel &pa) {
  x = root(x, pa);
  y = root(y, pa);
  if (x != y) {
    pa[x] = y;
  }
  return (x != y);
}
int gcd(int x, int y) {
  if (x < y) {
    return gcd(y, x);
  }
  if (y == 0) {
    return x;
  }
  return gcd(y, x % y);
}
int lcm(int x, int y) {
  x = abs(x);
  y = abs(y);
  return x * (y / gcd(x, y));
}
long long modinv(long long a, long long m) {
  long long b = m, u = 1, v = 0;
  while (b) {
    long long t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= m;
  if (u < 0)
    u += m;
  return u;
}
void make_inv(int max_inv, int p) {
  inv = vel(max_inv + 1, 1);
  for (int i = 2; i <= max_inv; i++) {
    inv[i] = p - ((p / i) * inv[p % i]) % p;
  }
}
void make_kai(int max_kai, int p) {
  kai = vel(max_kai + 1, 1);
  inv_kai = kai;
  make_inv(max_kai, p);
  rep(i, max_kai) {
    kai[i + 1] = kai[i] * (i + 1);
    kai[i + 1] %= p;
    inv_kai[i + 1] = inv_kai[i] * inv[i + 1];
    inv_kai[i + 1] %= p;
  }
}
int com(int n, int r, int p) {
  if ((n < 0) || (r < 0) || (r > n)) {
    return 0;
  }
  int ans = (kai[n] * inv_kai[r]) % p;
  return (ans * inv_kai[n - r]) % p;
}
int per(int n, int r, int p) {
  if ((n < 0) || (r < 0) || (r > n)) {
    return 0;
  }
  return (kai[n] * inv_kai[n - r]) % p;
}
vel uni(vel x) {
  if (x.size() == 0) {
    return x;
  }
  sor(x);
  int n = x.size();
  vel ans(1, x[0]);
  for (int j = 1; j < n; j++) {
    if (x[j - 1] != x[j]) {
      ans.push_back(x[j]);
    }
  }
  x = ans;
  return x;
}
vel dijk(V<V<pin>> &way, int st, int inf) {
  int n = way.size();
  vel dist(n, inf);
  dist[st] = 0;
  priority_queue<pin, vector<pin>, greater<pin>> pq;
  pq.push(mkp(0, st));
  veb is_checked(n, false);
  while (!pq.empty()) {
    pin x = pq.top();
    pq.pop();
    int pot = x.second;
    if (!is_checked[pot]) {
      is_checked[pot] = true;
      for (auto y : way[pot]) {
        int nex_dist = x.first + y.second;
        int nex_pot = y.first;
        if (dist[nex_pot] > nex_dist) {
          dist[nex_pot] = nex_dist;
          pq.push(mkp(nex_dist, y.first));
        }
      }
    }
  }
  return dist;
}
void make_tree(vvel &chi, vel &par, int n) {
  V<V<pin>> way(n);
  rep(i, n - 1) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    way[a].push_back(mkp(b, 1));
    way[b].push_back(mkp(a, 1));
  }
  vel dist = dijk(way, 0, n + 1);
  par = vel(n, -1);
  chi = vvel(n);
  rep(i, n) {
    for (auto nex : way[i]) {
      int pot = nex.first;
      if (dist[pot] > dist[i]) {
        chi[i].push_back(pot);
      } else {
        par[i] = pot;
      }
    }
  }
}
void pri(vel &v) {
  if (v.size() == 0) {
    return;
  }
  cout << v[0];
  rep(i, v.size() - 1) { cout << " " << v[i + 1]; }
  cout << endl;
  return;
}
int modpow(int a, int n, int p) {
  if (n == 0) {
    return 1;
  }
  int m = n / 2;
  int x = modpow(a, n / 2, p);
  x *= x;
  x %= p;
  if (n % 2 == 1) {
    x *= a;
    x %= p;
  }
  return x;
}
#define ui long long
vvel disj_min(vel &v) {
  int n = v.size();
  vvel ret(22, vel(n));
  ret[0] = v;
  rep(i, 21) {
    rep(j, n) {
      int nex = j + (1 << i);
      if (nex < n) {
        ret[i + 1][j] = min(ret[i][j], ret[i][nex]);
      } else {
        ret[i + 1][j] = ret[i][j];
      }
    }
  }
  return ret;
}
int find_min(vvel &dv, int l, int r) {
  int i = 21;
  while (l + (1 << i) > r) {
    i--;
  }
  while (i >= 0) {
    if (dv[i][l] > dv[i][r - (1 << i)]) {
      l = r - (1 << i);
    } else {
      r = l + (1 << i);
    }
    i--;
  }
  return l;
}
void sol(V<string> &t, int i, string u) {
  t.push_back(u);
  if (i < u.size()) {
    sol(t, i + 1, u);
    u[i] = '.';
    sol(t, i + 1, u);
  }
}
V<V<pin>> dbl(V<pin> &v) {
  V<V<pin>> ans(20, V<pin>(v));
  int n = v.size();
  rep(i, 19) {
    rep(j, n) {
      ans[i + 1][j].first = ans[i][ans[i][j].first].first;
      ans[i + 1][j].second =
          max(ans[i][j].second, ans[i][ans[i][j].first].second);
    }
  }
  return ans;
}
int lca(int s, int t, int diff, V<V<pin>> &pa) {
  if (diff < 0) {
    return lca(t, s, -diff, pa);
  }
  int ans = 0;
  rep(i, 19) {
    if ((diff & (1 << i)) != 0) {
      mmax(ans, pa[i][s].second);
      s = pa[i][s].first;
    }
  }
  for (int i = 19; i >= 0; i--) {
    if (pa[i][s] != pa[i][t]) {
      mmax(ans, pa[i][s].second);
      s = pa[i][s].first;
      mmax(ans, pa[i][t].second);
      t = pa[i][t].first;
    }
  }
  if (s != t) {
    mmax(ans, pa[0][s].second);
    mmax(ans, pa[0][t].second);
  }
  return ans;
}
void alp(int n, vel &pr) {
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      pr.push_back(i);
      while (n % i == 0) {
        n /= i;
      }
    }
  }
  if (n != 1) {
    pr.push_back(n);
  }
}
vel dx = {0, 0, -1, 1};
vel dy = {1, -1, 0, 0};
signed main() {
  omajinai;
  int l, r;
  cin >> l >> r;
  if (l - r >= 700) {
    cout << 0 << endl;
    return 0;
  }
  int ans = 2019;
  for (int i = l; i <= r; i++) {
    for (int j = i + 1; j <= r; j++) {
      mmin(ans, (i * j) % 2019);
    }
  }
  cout << ans << endl;
  return 0;
}


Fixed submission:
#include <algorithm>
#include <array>
#include <bitset>
#include <cmath>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#define M_PI 3.141592653589793238
using namespace std;
long long p9 = 998244353;
long long p1 = 1000000007;
#define upperbound(v, val) upper_bound(v.begin(), v.end(), val) - v.begin()
#define lowerbound(v, val) lower_bound(v.begin(), v.end(), val) - v.begin()
#define int long long
#define vel vector<long long>
#define vvel vector<vel>
#define rep(i, n) for (int i = 0; i < n; i++)
#define sor(v) sort(v.begin(), v.end())
#define mmax(a, b) a = max(a, b)
#define mmin(a, b) a = min(a, b)
#define mkp(a, b) make_pair(a, b)
#define pin pair<int, int>
#define qin pair<pin, int>
#define V vector
#define Endl endl
#define veb vector<bool>
#define fcout cout << fixed << setprecision(15)
#define rev(s) reverse(s.begin(), s.end())
#define lower(h, val) (lower_bound(h.begin(), h.end(), val) - h.begin())
#define upper(h, val) (upper_bound(h.begin(), h.end(), val) - h.begin())
#define vveb V<veb>
#define omajinai                                                               \
  cin.tie(0);                                                                  \
  ios::sync_with_stdio(false);
#define endl "\n"
#define pb push_back
vel kai;
vel inv_kai;
vel inv;
int root(int x, vel &pa) {
  if (pa[x] == -1) {
    return x;
  }
  int ans = root(pa[x], pa);
  pa[x] = ans;
  return ans;
}
bool mar(int x, int y, vel &pa) {
  x = root(x, pa);
  y = root(y, pa);
  if (x != y) {
    pa[x] = y;
  }
  return (x != y);
}
int gcd(int x, int y) {
  if (x < y) {
    return gcd(y, x);
  }
  if (y == 0) {
    return x;
  }
  return gcd(y, x % y);
}
int lcm(int x, int y) {
  x = abs(x);
  y = abs(y);
  return x * (y / gcd(x, y));
}
long long modinv(long long a, long long m) {
  long long b = m, u = 1, v = 0;
  while (b) {
    long long t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= m;
  if (u < 0)
    u += m;
  return u;
}
void make_inv(int max_inv, int p) {
  inv = vel(max_inv + 1, 1);
  for (int i = 2; i <= max_inv; i++) {
    inv[i] = p - ((p / i) * inv[p % i]) % p;
  }
}
void make_kai(int max_kai, int p) {
  kai = vel(max_kai + 1, 1);
  inv_kai = kai;
  make_inv(max_kai, p);
  rep(i, max_kai) {
    kai[i + 1] = kai[i] * (i + 1);
    kai[i + 1] %= p;
    inv_kai[i + 1] = inv_kai[i] * inv[i + 1];
    inv_kai[i + 1] %= p;
  }
}
int com(int n, int r, int p) {
  if ((n < 0) || (r < 0) || (r > n)) {
    return 0;
  }
  int ans = (kai[n] * inv_kai[r]) % p;
  return (ans * inv_kai[n - r]) % p;
}
int per(int n, int r, int p) {
  if ((n < 0) || (r < 0) || (r > n)) {
    return 0;
  }
  return (kai[n] * inv_kai[n - r]) % p;
}
vel uni(vel x) {
  if (x.size() == 0) {
    return x;
  }
  sor(x);
  int n = x.size();
  vel ans(1, x[0]);
  for (int j = 1; j < n; j++) {
    if (x[j - 1] != x[j]) {
      ans.push_back(x[j]);
    }
  }
  x = ans;
  return x;
}
vel dijk(V<V<pin>> &way, int st, int inf) {
  int n = way.size();
  vel dist(n, inf);
  dist[st] = 0;
  priority_queue<pin, vector<pin>, greater<pin>> pq;
  pq.push(mkp(0, st));
  veb is_checked(n, false);
  while (!pq.empty()) {
    pin x = pq.top();
    pq.pop();
    int pot = x.second;
    if (!is_checked[pot]) {
      is_checked[pot] = true;
      for (auto y : way[pot]) {
        int nex_dist = x.first + y.second;
        int nex_pot = y.first;
        if (dist[nex_pot] > nex_dist) {
          dist[nex_pot] = nex_dist;
          pq.push(mkp(nex_dist, y.first));
        }
      }
    }
  }
  return dist;
}
void make_tree(vvel &chi, vel &par, int n) {
  V<V<pin>> way(n);
  rep(i, n - 1) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    way[a].push_back(mkp(b, 1));
    way[b].push_back(mkp(a, 1));
  }
  vel dist = dijk(way, 0, n + 1);
  par = vel(n, -1);
  chi = vvel(n);
  rep(i, n) {
    for (auto nex : way[i]) {
      int pot = nex.first;
      if (dist[pot] > dist[i]) {
        chi[i].push_back(pot);
      } else {
        par[i] = pot;
      }
    }
  }
}
void pri(vel &v) {
  if (v.size() == 0) {
    return;
  }
  cout << v[0];
  rep(i, v.size() - 1) { cout << " " << v[i + 1]; }
  cout << endl;
  return;
}
int modpow(int a, int n, int p) {
  if (n == 0) {
    return 1;
  }
  int m = n / 2;
  int x = modpow(a, n / 2, p);
  x *= x;
  x %= p;
  if (n % 2 == 1) {
    x *= a;
    x %= p;
  }
  return x;
}
#define ui long long
vvel disj_min(vel &v) {
  int n = v.size();
  vvel ret(22, vel(n));
  ret[0] = v;
  rep(i, 21) {
    rep(j, n) {
      int nex = j + (1 << i);
      if (nex < n) {
        ret[i + 1][j] = min(ret[i][j], ret[i][nex]);
      } else {
        ret[i + 1][j] = ret[i][j];
      }
    }
  }
  return ret;
}
int find_min(vvel &dv, int l, int r) {
  int i = 21;
  while (l + (1 << i) > r) {
    i--;
  }
  while (i >= 0) {
    if (dv[i][l] > dv[i][r - (1 << i)]) {
      l = r - (1 << i);
    } else {
      r = l + (1 << i);
    }
    i--;
  }
  return l;
}
void sol(V<string> &t, int i, string u) {
  t.push_back(u);
  if (i < u.size()) {
    sol(t, i + 1, u);
    u[i] = '.';
    sol(t, i + 1, u);
  }
}
V<V<pin>> dbl(V<pin> &v) {
  V<V<pin>> ans(20, V<pin>(v));
  int n = v.size();
  rep(i, 19) {
    rep(j, n) {
      ans[i + 1][j].first = ans[i][ans[i][j].first].first;
      ans[i + 1][j].second =
          max(ans[i][j].second, ans[i][ans[i][j].first].second);
    }
  }
  return ans;
}
int lca(int s, int t, int diff, V<V<pin>> &pa) {
  if (diff < 0) {
    return lca(t, s, -diff, pa);
  }
  int ans = 0;
  rep(i, 19) {
    if ((diff & (1 << i)) != 0) {
      mmax(ans, pa[i][s].second);
      s = pa[i][s].first;
    }
  }
  for (int i = 19; i >= 0; i--) {
    if (pa[i][s] != pa[i][t]) {
      mmax(ans, pa[i][s].second);
      s = pa[i][s].first;
      mmax(ans, pa[i][t].second);
      t = pa[i][t].first;
    }
  }
  if (s != t) {
    mmax(ans, pa[0][s].second);
    mmax(ans, pa[0][t].second);
  }
  return ans;
}
void alp(int n, vel &pr) {
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      pr.push_back(i);
      while (n % i == 0) {
        n /= i;
      }
    }
  }
  if (n != 1) {
    pr.push_back(n);
  }
}
vel dx = {0, 0, -1, 1};
vel dy = {1, -1, 0, 0};
signed main() {
  omajinai;
  int l, r;
  cin >> l >> r;
  if (r - l >= 700) {
    cout << 0 << endl;
    return 0;
  }
  int ans = 2019;
  for (int i = l; i <= r; i++) {
    for (int j = i + 1; j <= r; j++) {
      mmin(ans, (i * j) % 2019);
    }
  }
  cout << ans << endl;
  return 0;
}