Language: C++

#include <iostream>
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
#define MAXSIZE 10000000;

bool comp(const pair<int,int> a, const pair<int,int> b) {
    return a.second < b.second;
}

const int MAX = 510000;
const int MOD = 1000000007;

int main(){
    ll L,R;

    cin >>L>>R;

    if( (R - L )>= 2019){
      cout <<0<<endl;
      return 0;
    }
    else{
      int minMod;
      for(ll i = L;i<R;i++){
        for(ll j = i+1;j<=R;j++){
          minMod = min(minMod,(i*j)%2019);
        }
      }

      cout <<minMod<<endl;
    }
}

/*Syakutori
while(cin >>b && b)){
      ll t = 1;
      long long int ansS = 1,ansT=0;
      long long int sum = 0;

      for(ll s = 1;s < 50000000;s++){

        while(t <  50000000 && sum+Rsum[t] < b){
          sum += Rsum[t];
          t++;
        }
        if(b == sum+Rsum[t]){
          if(ansT - ansS < t-s){
            ansS = s;
            ansT = t;
          }
          cout <<ansS<<" "<<ansT-ansS + 1<<endl;
          break;
        }
        if(t == s)++t;
        else sum -= Rsum[s];
        }
    }

//priority_queue<long long int,vector<long long int>, greater<long long int>> PQ;
//priority_queue<long long int> PQ1;

*/

Compiler output:
a.cc: In function 'int main()':
a.cc:27:23: error: no matching function for call to 'min(int&, ll)'
   27 |           minMod = min(minMod,(i*j)%2019);
      |                    ~~~^~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:233:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::min(const _Tp&, const _Tp&)'
  233 |     min(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:233:5: note:   template argument deduction/substitution failed:
a.cc:27:23: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'll' {aka 'long long int'})
   27 |           minMod = min(minMod,(i*j)%2019);
      |                    ~~~^~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::min(const _Tp&, const _Tp&, _Compare)'
  281 |     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_algo.h:5686:5: note: candidate: 'template<class _Tp> constexpr _Tp std::min(initializer_list<_Tp>)'
 5686 |     min(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5686:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5696:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::min(initializer_list<_Tp>, _Compare)'
 5696 |     min(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5696:5: note:   template argument deduction/substitution failed:
a.cc:27:23: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   27 |           minMod = min(minMod,(i*j)%2019);
      |                    ~~~^~~~~~~~~~~~~~~~~~~