Language: C++

#include<iostream>
#include<set>
#include<tuple>
#include<vector>

using namespace std;

typedef pair<char,char> PII;
typedef tuple<set<PII>,set<PII>,set<PII> > T;

bool neighbor(const set<PII> &s,PII p){
  for(int i=0;i<4;i++){
    static int d[]={0,1,0,-1,0};
    auto pp=make_pair(p.first+d[i],p.second+d[i+1]);
    if(s.count(pp))return true;
  }
  return false;
}

int main(){
  for(int w,h;cin>>w>>h,w;){
    set<PII> s;
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
	int r;
	cin>>r;
	if(r){
	  s.insert({i,j});
	}
      }
    }
    auto b=*s.begin();
    s.erase(s.begin());
    bool flag=false;
    if(s.size()%2){
      for(auto e:s){
	auto is=s;
	is.erase(e);
	for(int i=0;i<4;i++){
	  for(int j=0;j<2;j++){
	    set<T> ss;
	    set<PII> bs,es;
	    bs.insert(b);
	    es.insert(e);
	    T ist{bs,es,is};
	    vector<T> v{ist};
	    while(!v.empty()){
	      auto cs=v.back();
	      if(get<2>(cs).empty())break;
	      v.pop_back();
	      if(!ss.insert(cs).second)continue;
	      //	      cout<<get<2>(cs).size()<<endl;
	      for(auto f:get<2>(cs)){
		auto vec=make_pair(f.first-b.first,f.second-b.second);
		if(j){
		  swap(vec.first,vec.second);
		}
		for(int k=0;k<i;k++){
		  vec=make_pair(-vec.second,vec.first);
		}
		auto d=make_pair(e.first+vec.first,e.second+vec.second);
		const auto &rs=get<2>(cs);
		if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
		  auto ns=cs;
		  get<0>(ns).insert(f);
		  get<1>(ns).insert(d);
		  get<2>(ns).erase(f);
		  get<2>(ns).erase(d);
		  v.push_back(ns);
		}
	      }
	    }
	    flag|=!v.empty();
	  }
	}
      }
    }
    cout<<(flag?"YES":"NO")<<endl;
  }
}

		  
    

Compiler output:
a.cc: In function 'int main()':
a.cc:63:21: error: no match for 'operator!=' (operand types are 'std::pair<int, int>' and 'std::pair<char, char>')
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                    ~^~~
      |                    |  |
      |                    |  pair<char,char>
      |                    pair<int,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:63:23: note:   'std::pair<int, int>' is not derived from 'const std::fpos<_StateT>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
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:63:23: note:   'std::pair<int, int>' is not derived from 'const std::allocator<_CharT>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
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:63:23: note:   'std::pair<int, int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/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:63:23: note:   'std::pair<int, int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/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:63:23: note:   'std::pair<int, int>' is not derived from 'const std::move_iterator<_IteratorL>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/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:63:23: note:   'std::pair<int, int>' is not derived from 'const std::move_iterator<_IteratorL>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
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:63:23: note:   deduced conflicting types for parameter '_T1' ('int' and 'char')
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
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:63:23: note:   'std::pair<int, int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/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:63:23: note:   'std::pair<int, int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/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:63:23: note:   'std::pair<char, char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/usr/include/c++/14/bits/basic_string.h:3833:5: 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>&)'
 3833 |     operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3833:5: note:   template argument deduction/substitution failed:
a.cc:63:23: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/usr/include/c++/14/bits/basic_string.h:3847:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator!=(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3847 |     operator!=(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3847:5: note:   template argument deduction/substitution failed:
a.cc:63:23: note:   mismatched types 'const _CharT*' and 'std::pair<int, int>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
/usr/include/c++/14/bits/basic_string.h:3860:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator!=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3860 |     operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3860:5: note:   template argument deduction/substitution failed:
a.cc:63:23: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
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:2613:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator!=(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2613 |     operator!=(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2613:5: note:   template argument deduction/substitution failed:
a.cc:63:23: note:   'std::pair<int, int>' is not derived from 'const std::tuple<_UTypes ...>'
   63 |                 if(d!=f&&rs.count(d)&&neighbor(get<0>(cs),f)&&neighbor(get<1>(cs),d)){
      |                       ^
In file included from /usr/include/c++/14/bits/locale_facets.h:48,
                 from /usr/include/c++/14/bits/basic_ios.h:37,
                 from /usr/include/c++/14/ios:46:
/usr/include/c++/14/bits/streambuf_iterator.h:242:5: note: candidate: 'template<class _CharT, class _Traits> bool std::operator!=(cons