Language: C++

#include <bits/stdc++.h>
#include <numeric>
#define REP(i, s, n) for (int i = s; i < n; ++i)
#define rep(i, n) REP(i, 0, n)
#define SORT(c) sort((c).begin(), (c).end())
#define SORT_INV(c) sort((c).begin(), (c).end(), greater<int>())
#define IINF INT_MAX
#define LLINF LLONG_MAX
#define DEBUG false
#define LL long long
#define Num 1000000007
// sort(a.begin(), a.end(), std::greater<int>());
using namespace std;

int find(int x, int y)
{
    int ans = INT_MAX;
    rep(i, x)
    {
        vector<long long int > a(3);
        a[0] = i * y;
        int div = y / 2;
        a[1] = (x - i) * div;
        a[2] = (x - i) * (y - div);
        SORT(a);
        if (DEBUG)
            cout << a[0] << " " << a[1] << " " << a[2] << endl;
        ans = min(ans, a[2] - a[0]);
        div = (x - i) / 2;
        a[0] = i * y;
        a[1] = y * div;
        a[2] = y * (x - i - div);
        SORT(a);
        if (DEBUG)
            cout << a[0] << " " << a[1] << " " << a[2] << endl;
        ans = min(ans, a[2] - a[0]);
    }
    return ans;
}
int main()
{
    int h, w;
    cin >> h >> w;
    cout << min(find(h, w), find(w, h)) << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int find(int, int)':
a.cc:28:18: error: no matching function for call to 'min(int&, __gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type)'
   28 |         ans = min(ans, a[2] - a[0]);
      |               ~~~^~~~~~~~~~~~~~~~~~
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: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:28:18: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'})
   28 |         ans = min(ans, a[2] - a[0]);
      |               ~~~^~~~~~~~~~~~~~~~~~
/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:
/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:28:18: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   28 |         ans = min(ans, a[2] - a[0]);
      |               ~~~^~~~~~~~~~~~~~~~~~
a.cc:36:18: error: no matching function for call to 'min(int&, __gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type)'
   36 |         ans = min(ans, a[2] - a[0]);
      |               ~~~^~~~~~~~~~~~~~~~~~
/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:36:18: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'})
   36 |         ans = min(ans, a[2] - a[0]);
      |               ~~~^~~~~~~~~~~~~~~~~~
/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
/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:36:18: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   36 |         ans = min(ans, a[2] - a[0]);
      |               ~~~^~~~~~~~~~~~~~~~~~