Language: C++

#include <bits/stdc++.h>
typedef long long LL;
#define SORT(c) sort((c).begin(),(c).end())
 
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
 
using namespace std;
int main(void)
{
  string s;
  cin >> s;
  int m[256];
  REP(i,26) m['a'+i]=(1<<i);
  int tmp=0;
  map<int,int> v;
  for(auto i=s.begin();i!=s.end();++i){
    tmp=(tmp^m[(int)s[i]]);
    d[tmp]=-33554432;
  }
  priority_queue<pair<int,int> > q; // negc, v;
  q.push(0,0);
  d[0]=0;
  while(!q.empty()) {
    int nc,v;
    tie(c,v) = q.top();
    q.pop();
    REP(i,26){
      if(d[v^(1<<i)]<c-1){
        q.push(make_pair(v^(1<<i),c-1));
        d[v^(1<<i)]=c-1;
      }
    }
  }
  cout << max(1,-d[tmp]) << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:22: error: no match for 'operator[]' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and '__gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> >')
   18 |     tmp=(tmp^m[(int)s[i]]);
      |                      ^
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/basic_string.h:1247:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::const_reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::operator[](size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; const_reference = const char&; size_type = long unsigned int]'
 1247 |       operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:1247:29: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> >' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1247 |       operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
      |                   ~~~~~~~~~~^~~~~
/usr/include/c++/14/bits/basic_string.h:1265:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::operator[](size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; reference = char&; size_type = long unsigned int]'
 1265 |       operator[](size_type __pos)
      |       ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:1265:28: note:   no known conversion for argument 1 from '__gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> >' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1265 |       operator[](size_type __pos)
      |                  ~~~~~~~~~~^~~~~
a.cc:19:5: error: 'd' was not declared in this scope
   19 |     d[tmp]=-33554432;
      |     ^
a.cc:22:9: error: no matching function for call to 'std::priority_queue<std::pair<int, int> >::push(int, int)'
   22 |   q.push(0,0);
      |   ~~~~~~^~~~~
In file included from /usr/include/c++/14/queue:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:157:
/usr/include/c++/14/bits/stl_queue.h:736:7: note: candidate: 'void std::priority_queue<_Tp, _Sequence, _Compare>::push(const value_type&) [with _Tp = std::pair<int, int>; _Sequence = std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >; _Compare = std::less<std::pair<int, int> >; value_type = std::pair<int, int>]'
  736 |       push(const value_type& __x)
      |       ^~~~
/usr/include/c++/14/bits/stl_queue.h:736:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_queue.h:744:7: note: candidate: 'void std::priority_queue<_Tp, _Sequence, _Compare>::push(value_type&&) [with _Tp = std::pair<int, int>; _Sequence = std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >; _Compare = std::less<std::pair<int, int> >; value_type = std::pair<int, int>]'
  744 |       push(value_type&& __x)
      |       ^~~~
/usr/include/c++/14/bits/stl_queue.h:744:7: note:   candidate expects 1 argument, 2 provided
a.cc:23:3: error: 'd' was not declared in this scope
   23 |   d[0]=0;
      |   ^
a.cc:26:9: error: 'c' was not declared in this scope
   26 |     tie(c,v) = q.top();
      |         ^