Language: C++

#include <bits/stdc++.h>

using namespace std;

map < int, int > H;
int N, sol, a[100005];

int main() {
    ios_base::sync_with_stdio(false);
    cin >> N;
    
    for (int i = 1; i <= N; ++i) {
        int x; cin >> x;
        if (H[x]) {
            H[x] = 0;
        } else {
            H[x] = 1;
        }
        a[i] = x;
    }
    
    for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
        if (it -> second > 0) {
            ++sol;
        }
    
    cout << sol << '\n';
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:22:49: error: conversion from '_Rb_tree_iterator<pair<const int,[...]>>' to non-scalar type '_Rb_tree_iterator<pair<const char,[...]>>' requested
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                          ~~~~~~~^~
a.cc:22:55: error: no match for 'operator!=' (operand types are 'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} and 'std::map<int, int>::iterator' {aka 'std::_Rb_tree<int, std::pair<const int, int>, std::_Select1st<std::pair<const int, int> >, std::less<int>, std::allocator<std::pair<const int, int> > >::iterator'})
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                     ~~^~~~~~~~~
      |                                                     |        |
      |                                                     |        _Rb_tree_iterator<pair<const int,[...]>>
      |                                                     _Rb_tree_iterator<pair<const char,[...]>>
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1132:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1132 |     operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1132:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:1212:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator!=(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1212 |     operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1212:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:1305:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1305 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1305:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:1379:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1379 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1379:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<int, int>::iterator' {aka 'std::_Rb_tree<int, std::pair<const int, int>, std::_Select1st<std::pair<const int, int> >, std::less<int>, std::allocator<std::pair<const int, int> > >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:1473:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1473 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1473:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:1547:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1547 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1547:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<int, int>::iterator' {aka 'std::_Rb_tree<int, std::pair<const int, int>, std::_Select1st<std::pair<const int, int> >, std::less<int>, std::allocator<std::pair<const int, int> > >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:1647:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1647 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1647:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/regex.h:2213:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator!=(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2213 |     operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2213:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 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_pair.h:1052:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1052 |     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1052:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::pair<_T1, _T2>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:455:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  455 |     operator!=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:455:5: note:   template argument deduction/substitution failed:
a.cc:22:63: note:   'std::map<char, int>::iterator' {aka 'std::_Rb_tree<char, std::pair<const char, int>, std::_Select1st<std::pair<const char, int> >, std::less<char>, std::allocator<std::pair<const char, int> > >::iterator'} is not derived from 'const std::reverse_iterator<_Iterator>'
   22 |     for (std::map<char,int>::iterator it=H.begin(); it!=H.end(); ++it)
      |                                                               ^
/usr/include/c++/14/bits/stl_iterator.h:500:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  500 |     operator!=(const reverse_itera