Language: C++

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;

#define INF 1<<30
#define LINF 1ll<<60ll
#define MOD 1000000007
#define pb(a) push_back(a)

#define _overload3(_1,_2,_3,_4,name,...) name
#define _rep(i,n) _repi(i,0,n)
#define _repi(i,a,b) for(int i=a, i##_len=(b); i<i##_len; ++i)
#define _repis(i,a,b,s) for(int i=a, i##_len(b); i<i##_len; i+=s)
#define REP(...) _overload3(__VA_ARGS__,_repis,_repi,_rep,)(__VA_ARGS__)

#define REPR(i, n) for(int i = n;i >= 0;--i)
#define REPARR(i, v) for(int i = 0;i < sz(v);++i)

#define all(vec) (vec.begin()),(vec.end())
#define sz(x) ((int)(x).size())
#define bit(n) (1ll<<(n))

template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(a>b){a=b;return true;}return false;}

#define YES(n) cout<<((n)?"YES":"NO")<<endl
#define Yes(n) cout<<((n)?"Yes":"No")<<endl
#define yes(n) cout<<((n)?"yes":"no")<<endl
#define poss(n) cout<<((n)?"possible":"impossible")<<endl
#define Poss(n) cout<<((n)?"Possible":"Impossible")<<endl
#define POSS(n) cout<<((n)?"POSSIBLE":"IMPOSSIBLE")<<endl



int main(){
    string s;
    cin>>s;
    vector<bool> x(26);
    REPARR(i,s){
        x[s[i]-'a']^=1;
    }
    bool flag=true;
    REP(i,26){
        if(s[i])flag=false;
    }
    Yes(flag);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:48:20: error: no match for 'operator^=' (operand types are 'std::vector<bool>::reference' and 'int')
   48 |         x[s[i]-'a']^=1;
      |         ~~~~~~~~~~~^~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41,
                 from a.cc:1:
/usr/include/c++/14/cstddef:178:3: note: candidate: 'constexpr std::byte& std::operator^=(byte&, byte)'
  178 |   operator^=(byte& __l, byte __r) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/cstddef:178:20: note:   no known conversion for argument 1 from 'std::vector<bool>::reference' to 'std::byte&'
  178 |   operator^=(byte& __l, byte __r) noexcept
      |              ~~~~~~^~~
In file included from /usr/include/c++/14/streambuf:43,
                 from /usr/include/c++/14/bits/streambuf_iterator.h:35,
                 from /usr/include/c++/14/iterator:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:54:
/usr/include/c++/14/bits/ios_base.h:114:3: note: candidate: 'constexpr const std::_Ios_Fmtflags& std::operator^=(_Ios_Fmtflags&, _Ios_Fmtflags)'
  114 |   operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:114:29: note:   no known conversion for argument 1 from 'std::vector<bool>::reference' to 'std::_Ios_Fmtflags&'
  114 |   operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |              ~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:164:3: note: candidate: 'constexpr const std::_Ios_Openmode& std::operator^=(_Ios_Openmode&, _Ios_Openmode)'
  164 |   operator^=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:164:29: note:   no known conversion for argument 1 from 'std::vector<bool>::reference' to 'std::_Ios_Openmode&'
  164 |   operator^=(_Ios_Openmode& __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |              ~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:211:3: note: candidate: 'constexpr const std::_Ios_Iostate& std::operator^=(_Ios_Iostate&, _Ios_Iostate)'
  211 |   operator^=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:211:28: note:   no known conversion for argument 1 from 'std::vector<bool>::reference' to 'std::_Ios_Iostate&'
  211 |   operator^=(_Ios_Iostate& __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |              ~~~~~~~~~~~~~~^~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:176:
/usr/include/c++/14/future:189:18: note: candidate: 'constexpr std::launch& std::operator^=(launch&, launch)'
  189 |   inline launch& operator^=(launch& __x, launch __y) noexcept
      |                  ^~~~~~~~
/usr/include/c++/14/future:189:37: note:   no known conversion for argument 1 from 'std::vector<bool>::reference' to 'std::launch&'
  189 |   inline launch& operator^=(launch& __x, launch __y) noexcept
      |                             ~~~~~~~~^~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:198:
/usr/include/c++/14/charconv:654:3: note: candidate: 'constexpr std::chars_format& std::operator^=(chars_format&, chars_format)'
  654 |   operator^=(chars_format& __lhs, chars_format __rhs) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/charconv:654:28: note:   no known conversion for argument 1 from 'std::vector<bool>::reference' to 'std::chars_format&'
  654 |   operator^=(chars_format& __lhs, chars_format __rhs) noexcept
      |              ~~~~~~~~~~~~~~^~~~~