Language: C++

#include <iostream>
#include <stdio.h>
#include <vector>
#include <algorithm> // sort
#include <map> // pair
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define REP(i, j, n) for (int i = j; i < (n); ++i)
using namespace std;
typedef long long ll;
typedef vector<int> vi;

int main(){
  int n;
  cin >>n;
  vi p[100000000];
  rep(i,n){
    int a;
    cin >> a;
    a--;
    if(p[a] >=1) p[a]--;
    else p[n]++;    
}
  int ans = 0;
  rep(i,1000000000){
    if(p[i]>0) ans++;
  }
  cout<<ans<<endl;

Compiler output:
a.cc: In function 'int main()':
a.cc:20:13: error: no match for 'operator>=' (operand types are 'vi' {aka 'std::vector<int>'} and 'int')
   20 |     if(p[a] >=1) p[a]--;
      |        ~~~~ ^~~
      |           |   |
      |           |   int
      |           vi {aka std::vector<int>}
In file included from /usr/include/c++/14/string:48,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:476:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  476 |     operator>=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:476:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/bits/stl_iterator.h:520:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  520 |     operator>=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:520:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1724 |     operator>=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1781 |     operator>=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1070:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator>=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1070 |     operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1070:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::pair<_T1, _T2>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:739:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  739 |     operator>=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:739:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'std::vector<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/string_view:746:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  746 |     operator>=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:746:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'std::vector<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/string_view:754:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  754 |     operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:754:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/bits/basic_string.h:3997:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3997 |     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3997:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/bits/basic_string.h:4011:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 4011 |     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4011:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
/usr/include/c++/14/bits/basic_string.h:4024:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4024 |     operator>=(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4024:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   mismatched types 'const _CharT*' and 'std::vector<int>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2631:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator>=(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2631 |     operator>=(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2631:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::tuple<_UTypes ...>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
In file included from /usr/include/c++/14/vector:66,
                 from a.cc:3:
/usr/include/c++/14/bits/stl_vector.h:2114:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator>=(const vector<_Tp, _Alloc>&, const vector<_Tp, _Alloc>&)'
 2114 |     operator>=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:2114:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   mismatched types 'const std::vector<_Tp, _Alloc>' and 'int'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
In file included from /usr/include/c++/14/map:63,
                 from a.cc:5:
/usr/include/c++/14/bits/stl_map.h:1578:5: note: candidate: 'template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator>=(const map<_Key, _Tp, _Compare, _Allocator>&, const map<_Key, _Tp, _Compare, _Allocator>&)'
 1578 |     operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_map.h:1578:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::map<_Key, _Tp, _Compare, _Allocator>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
In file included from /usr/include/c++/14/map:64:
/usr/include/c++/14/bits/stl_multimap.h:1200:5: note: candidate: 'template<class _Key, class _Tp, class _Compare, class _Alloc> bool std::operator>=(const multimap<_Key, _Tp, _Compare, _Allocator>&, const multimap<_Key, _Tp, _Compare, _Allocator>&)'
 1200 |     operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_multimap.h:1200:5: note:   template argument deduction/substitution failed:
a.cc:20:15: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::multimap<_Key, _Tp, _Compare, _Allocator>'
   20 |     if(p[a] >=1) p[a]--;
      |               ^
a.cc:20:22: error: no 'operator--(int)' declared for postfix '--' [-fpermissive]
   20 |     if(p[a] >=1) p[a]--;
      |                  ~~~~^~
a.cc:21:14: error: no 'operator++(int)' declared for postfix '++' [-fpermissive]
   21 |     else p[n]++;
      |          ~~~~^~
a.cc:25:12: error: no match for 'operator>' (operand types are 'vi' {aka 'std::vector<int>'} and 'int')
   25 |     if(p[i]>0) ans++;
      |        ~~~~^~
      |           | |
      |           | int
      |           vi {aka std::vector<int>}
/usr/include/c++/14/bit