Language: C++

#include <iostream>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <queue>
#include <cmath>

#define	MOD 1000000007;
#define PI 3.14159265358979323846;
using namespace std;
typedef long long ll;
ll mod = 1000000007;

ll pow(int a, int n)
{
	if (n == 0)
	{
		return 1;
	}

	if (n % 2 == 0)
	{
		return (pow(a, n / 2)* pow(a, n / 2) % mod);
	}
	else {
		return ((pow(a, n / 2)* pow(a, n / 2) % mod) * a % mod);
	}
}

int main()
{
	int N;
	cin >> N;

	ll A[10000];
	map<ll, int>mp;
	for (int i = 0; i < N; i++)
	{
		cin >> A[i];
		mp[A[i]]++;
	}

	int P = N / 2;
	bool isValid = true;
	if (N % 2 == 0)
	{
		if (mp.size() != P) {
			isValid = false;
		}
		for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
		{
			if (it->second != 2)
			{
				isValid = false;
			}
		}
	}
	else {
		if (mp.size() != P + 1) {
			isValid = false;
		}
		for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
		{
			if (it->first == 0)
			{
				if (it->second != 1)
				{
					isValid = false;
				}
			}
			else {
				if (it->second != 2)
				{
					isValid = false;
				}
			}
		}
	}

	if (!isValid)
	{
		cout << 0 << endl;
	}
	else {
		cout << pow(2, P) % mod << endl;
	}

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:52:59: error: conversion from '_Rb_tree_iterator<pair<const long long int,[...]>>' to non-scalar type '_Rb_tree_iterator<pair<const int,[...]>>' requested
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                   ~~~~~~~~^~
a.cc:52:66: error: no match for 'operator!=' (operand types are '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'} and 'std::map<long long int, int>::iterator' {aka 'std::_Rb_tree<long long int, std::pair<const long long int, int>, std::_Select1st<std::pair<const long long int, int> >, std::less<long long int>, std::allocator<std::pair<const long long int, int> > >::iterator'})
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                               ~~ ^~ ~~~~~~~~
      |                                                               |           |
      |                                                               |           _Rb_tree_iterator<pair<const long long int,[...]>>
      |                                                               _Rb_tree_iterator<pair<const int,[...]>>
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/postypes.h:197:5: note: candidate: 'template<class _StateT> bool std::operator!=(const fpos<_StateT>&, const fpos<_StateT>&)'
  197 |     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:197:5: note:   template argument deduction/substitution failed:
a.cc:52:76: 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::fpos<_StateT>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
In file included from /usr/include/c++/14/string:43,
                 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:
/usr/include/c++/14/bits/allocator.h:243:5: note: candidate: 'template<class _T1, class _T2> bool std::operator!=(const allocator<_CharT>&, const allocator<_T2>&)'
  243 |     operator!=(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:243:5: note:   template argument deduction/substitution failed:
a.cc:52:76: 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::allocator<_CharT>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
In file included from /usr/include/c++/14/string:48:
/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:52:76: 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::reverse_iterator<_Iterator>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.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_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:500:5: note:   template argument deduction/substitution failed:
a.cc:52:76: 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::reverse_iterator<_Iterator>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1686 |     operator!=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:52:76: 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::move_iterator<_IteratorL>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1753 |     operator!=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note:   template argument deduction/substitution failed:
a.cc:52:76: 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::move_iterator<_IteratorL>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
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: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:52:76: 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::pair<_T1, _T2>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
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:651:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  651 |     operator!=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:651:5: note:   template argument deduction/substitution failed:
a.cc:52:76: note:   'std::_Rb_tree_iterator<std::pair<const int, int> >' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
/usr/include/c++/14/string_view:658:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  658 |     operator!=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:658:5: note:   template argument deduction/substitution failed:
a.cc:52:76: note:   'std::_Rb_tree_iterator<std::pair<const int, int> >' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
/usr/include/c++/14/string_view:666:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  666 |     operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:666:5: note:   template argument deduction/substitution failed:
a.cc:52:76: note:   'std::_Rb_tree_iterator<std::pair<const long long int, int> >' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   52 |                 for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++)
      |                                                                            ^
/usr/include/c++/14/bits/basic_string.h:3833:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::opera