Language: C++

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main()
{
	string str;
	cin >> str;

	int full_size = str.size();
	
	string str_f_half = str.substr(0, (full_size - 1) / 2);
	string str_b_half = str.substr((full_size + 1) / 2, (full_size + 3) / 2);
	reverse(str_b_half.begin(), str_b_half.end());

	bool flag = false;

	if (str_f_half == str_b_half) {
		int half_size = str_f_half.size();
		string str_ff_quorter = str_f_half.substr(0, (half_size - 1) / 2);
		string str_fb_quorter = str_f_half.substr((half_size + 1) / 2, (half_size + 3) / 2);
		reverse(str_fb_quorter.begin(), str_fb_quorter.end());

		string str_bf_quorter = str_b_half.substr(0, (half_size - 1) / 2);
		string str_bb_quorter = str_b_half.substr((half_size + 1) / 2, (half_size + 3) / 2);
		reverse(str_bb_quorter.begin(), str_bb_quorter.end());

		if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;

		if (str_ff_quorter == str_fb_quorter && str_bf_quorter == str_bb_quorter) {
			flag = true;
		}
	}
	if (flag) {
		cout << "Yes" << endl;
	}
	else {
		cout << "No" << endl;
	}
}


Compiler output:
a.cc:30:39: error: empty character constant
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
a.cc:30:63: error: empty character constant
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                                               ^~
a.cc:30:87: error: empty character constant
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                                                                       ^~
a.cc:30:111: error: empty character constant
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                                                                                               ^~
a.cc: In function 'int main()':
a.cc:30:36: error: no match for 'operator==' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'char')
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                     ~~~~~~~~~~~~~~ ^~ ~~
      |                     |                 |
      |                     |                 char
      |                     std::string {aka std::__cxx11::basic_string<char>}
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:192:5: note: candidate: 'template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)'
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::fpos<_StateT>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
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:235:5: note: candidate: 'template<class _T1, class _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)'
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::allocator<_CharT>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
In file included from /usr/include/c++/14/string:48:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
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:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::pair<_T1, _T2>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
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:629:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  629 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:629:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/string_view:637:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  637 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:637:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/string_view:644:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  644 |     operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:644:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'char'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/bits/basic_string.h:3755:5: 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>&)'
 3755 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note:   template argument deduction/substitution failed:
a.cc:30:39: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'char'
   30 |                 if (str_ff_quorter == '' || str_fb_quorter == '' || str_bf_quorter == '' || str_bb_quorter == '') break;
      |                                       ^~
/usr/include/c++/14/bits/basic_string.h:3772:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3772 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c