Language: C++

// Bismillaahirrahmaanirrahiim
/* Author	: Jehian Norman Saviero (@Reiva5) */
#include <bits/stdc++.h>

/* MACROS SAMPAH */
#define jehian using
#define mau namespace
#define libur std
#define cepet {ios_base::sync_with_stdio(0);cin.tie(0);}

jehian mau libur;
/* MACROS FOR TYPE */
typedef long l;
typedef long double ld;
typedef long long ll;
typedef unsigned long ul;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<l> vl;
typedef vector<ll> vll;
typedef pair<int, int> pi;
typedef pair<l,l> pl;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pld;

/* MACROS FOR PRINT */
#define nl printf("\n");
#define sp printf(" ");

/* MACROS FOR FUNCTION AND METHOD */
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define RESET(x) memset((x), 0, sizeof(x))
#define SET(x,y) memset((x), (y), sizeof(x))

/* MACROS FOR ATTRIBUTE */
#define fi first
#define se second

/* MACROS FOR SCAN */
#define scc(x) scanf("%c", &x)
#define scd(x) scanf("%Lf", &x)
#define scf(x) scanf("%f", &x)
#define sci(x) scanf("%d", &x)
#define scl(x) scanf("%ld", &x)
#define scll(x) scanf("%lld", &x)
#define scld(x) scanf("%Lf", &x)
#define scui(x) sci(x)
#define scul(x) scl(x)
#define scull(x) scll(x)

ll data[256];
int main(){
	RESET(data);
	string S;
	cin >> S;
	for (auto x : S){
		++data[x];
	}
	ll hit[2];
	RESET(hit);
	for (ll i = 'a'; i <= 'z'; ++i){
		if (data[i]){
			++hit[data[i]%2];
		}
	}
	cout << max(hit[1],1) << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:55:15: error: reference to 'data' is ambiguous
   55 |         RESET(data);
      |               ^~~~
a.cc:34:26: note: in definition of macro 'RESET'
   34 | #define RESET(x) memset((x), 0, sizeof(x))
      |                          ^
In file included from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:3:
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:53:4: note:                 'll data [256]'
   53 | ll data[256];
      |    ^~~~
a.cc:55:15: error: reference to 'data' is ambiguous
   55 |         RESET(data);
      |               ^~~~
a.cc:34:40: note: in definition of macro 'RESET'
   34 | #define RESET(x) memset((x), 0, sizeof(x))
      |                                        ^
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:53:4: note:                 'll data [256]'
   53 | ll data[256];
      |    ^~~~
a.cc:59:19: error: reference to 'data' is ambiguous
   59 |                 ++data[x];
      |                   ^~~~
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:53:4: note:                 'll data [256]'
   53 | ll data[256];
      |    ^~~~
a.cc:64:21: error: reference to 'data' is ambiguous
   64 |                 if (data[i]){
      |                     ^~~~
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:53:4: note:                 'll data [256]'
   53 | ll data[256];
      |    ^~~~
a.cc:65:31: error: reference to 'data' is ambiguous
   65 |                         ++hit[data[i]%2];
      |                               ^~~~
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:53:4: note:                 'll data [256]'
   53 | ll data[256];
      |    ^~~~
a.cc:68:20: error: no matching function for call to 'max(ll&, int)'
   68 |         cout << max(hit[1],1) << endl;
      |                 ~~~^~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/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:68:20: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   68 |         cout << max(hit[1],1) << endl;
      |                 ~~~^~~~~~~~~~
/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:68:20: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   68 |         cout << max(hit[1],1) << endl;
      |                 ~~~^~~~~~~~~~