Language: C++

#include<bits/stdc++.h>
using namespace std;
#define int long long
int T,A,B,C,D;
int pd(int A,int B,int k){
	return (B+1)*k>=A&&(A+1)*k>=B;
}
char check(int A,int B,int z){
	int k=max((A-1)/(B+1),(B-1)/(A+1))+1;
	int l=0,r=A;
	while (l<r){
		int mid=(l+r+1)/2;
		if (pd(A-mid,B-(mid-1)/k,k))l=mid;
		else r=mid-1;
	}
	if (z<=l+(l-1)/k){
		if (z%(k+1)==0)return 'B';
		return 'A';
	}
	z-=l+max(0,(l-1)/k);
	A-=l;B-=max(0,(l-1)/k);
	int t=B%k;
	if (!t)t=k; 
	if (z<=t)return 'B';
	z-=t;B-=t;
	if (z%(k+1)==1)return 'A';
	return 'B';
}
signed main(){
	scanf("%lld",&T);
	while (T--){
		scanf("%lld%lld%lld%lld",&A,&B,&C,&D);
		for (int i=C;i<=D;i++)
			printf("%c",check(A,B,i));
		puts("");
	}
}

Compiler output:
a.cc: In function 'char check(long long int, long long int, long long int)':
a.cc:20:17: error: no matching function for call to 'max(int, long long int)'
   20 |         z-=l+max(0,(l-1)/k);
      |              ~~~^~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:20:17: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   20 |         z-=l+max(0,(l-1)/k);
      |              ~~~^~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:20:17: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   20 |         z-=l+max(0,(l-1)/k);
      |              ~~~^~~~~~~~~~~
a.cc:21:20: error: no matching function for call to 'max(int, long long int)'
   21 |         A-=l;B-=max(0,(l-1)/k);
      |                 ~~~^~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:21:20: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   21 |         A-=l;B-=max(0,(l-1)/k);
      |                 ~~~^~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:21:20: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   21 |         A-=l;B-=max(0,(l-1)/k);
      |                 ~~~^~~~~~~~~~~