Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
    ll H,W;
    cin>>H>>W;
    
    if(H%3==0||W%3==0){
        cout<<0<<endl;
        return 0;
    }
    
    if(H<W)swap(H,W);
    
    ll case1,case2;
    case1=case2=1e12;
    
    for(int i=0;i<2;i++){
        if(i)swap(H,W);
        if(H<3||W<2) break;
        
        ll S=(H+3-1)/3*W-H/3*W;
        
        ll a1=H/3*W;
        ll b1=(H-H/3)*(W/2);
        ll c1=(H-H/3)*((W+2-1)/2);
        ll s1=max({abs(a1-b1),abs(c1-b1),abs(c2-a2)});
        
        ll a2=(H+3-1)/3*W;
        ll b2=(H-(H+3-1)/3)*(W/2);
        ll c2=(H-(H+3-1)/3)*((W+2-1)/2);
        ll s2=max({abs(a2-b2),abs(c2-b2),abs(c2-a2)});
        
        case1=min(S,case1);
        case2=min({s1,s2,case2});
    }
    
    cout<<min(case1,case2)<<endl;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:27:46: error: 'c2' was not declared in this scope; did you mean 'c1'?
   27 |         ll s1=max({abs(a1-b1),abs(c1-b1),abs(c2-a2)});
      |                                              ^~
      |                                              c1
a.cc:27:49: error: 'a2' was not declared in this scope; did you mean 'a1'?
   27 |         ll s1=max({abs(a1-b1),abs(c1-b1),abs(c2-a2)});
      |                                                 ^~
      |                                                 a1
a.cc:27:18: error: no matching function for call to 'max(<brace-enclosed initializer list>)'
   27 |         ll s1=max({abs(a1-b1),abs(c1-b1),abs(c2-a2)});
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:   candidate expects 2 arguments, 1 provided
/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, 1 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:   template argument deduction/substitution failed:
/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:   candidate expects 2 arguments, 1 provided
a.cc:32:18: error: no matching function for call to 'max(<brace-enclosed initializer list>)'
   32 |         ll s2=max({abs(a2-b2),abs(c2-b2),abs(c2-a2)});
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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:   candidate expects 2 arguments, 1 provided
/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, 1 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:   template argument deduction/substitution failed:
/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:   candidate expects 2 arguments, 1 provided