/in/foo.cc: In function 'void SPFA()':
/in/foo.cc:37:22: error: reference to 'end' is ambiguous
    if(now==start&&v==end)continue;
                      ^~~
/in/foo.cc:6:25: note: candidates are: int end
 int n,m,x,y,z,c=0,start,end,ans=0x7fffffff;
                         ^~~
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/range_access.h:97:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::end(_Tp (&)[_Nm])
     end(_Tp (&__arr)[_Nm])
     ^~~
/usr/include/c++/6/bits/range_access.h:78:5: note:                 template<class _Container> decltype (__cont.end()) std::end(const _Container&)
     end(const _Container& __cont) -> decltype(__cont.end())
     ^~~
/usr/include/c++/6/bits/range_access.h:68:5: note:                 template<class _Container> decltype (__cont.end()) std::end(_Container&)
     end(_Container& __cont) -> decltype(__cont.end())
     ^~~
In file included from /usr/include/c++/6/bits/range_access.h:36:0,
                 from /usr/include/c++/6/string:51,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/initializer_list:99:5: note:                 template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)
     end(initializer_list<_Tp> __ils) noexcept
     ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:66:3: error: reference to 'end' is ambiguous
   end=e[i].to;
   ^~~
/in/foo.cc:6:25: note: candidates are: int end
 int n,m,x,y,z,c=0,start,end,ans=0x7fffffff;
                         ^~~
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/range_access.h:97:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::end(_Tp (&)[_Nm])
     end(_Tp (&__arr)[_Nm])
     ^~~
/usr/include/c++/6/bits/range_access.h:78:5: note:                 template<class _Container> decltype (__cont.end()) std::end(const _Container&)
     end(const _Container& __cont) -> decltype(__cont.end())
     ^~~
/usr/include/c++/6/bits/range_access.h:68:5: note:                 template<class _Container> decltype (__cont.end()) std::end(_Container&)
     end(_Container& __cont) -> decltype(__cont.end())
     ^~~
In file included from /usr/include/c++/6/bits/range_access.h:36:0,
                 from /usr/include/c++/6/string:51,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/initializer_list:99:5: note:                 template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)
     end(initializer_list<_Tp> __ils) noexcept
     ^~~
/in/foo.cc:68:10: error: reference to 'end' is ambiguous
   if(dis[end]==0x7fffffff)continue;//删掉一条边之后没有点可以到达它，那么就不构成环 
          ^~~
/in/foo.cc:6:25: note: candidates are: int end
 int n,m,x,y,z,c=0,start,end,ans=0x7fffffff;
                         ^~~
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/range_access.h:97:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::end(_Tp (&)[_Nm])
     end(_Tp (&__arr)[_Nm])
     ^~~
/usr/include/c++/6/bits/range_access.h:78:5: note:                 template<class _Container> decltype (__cont.end()) std::end(const _Container&)
     end(const _Container& __cont) -> decltype(__cont.end())
     ^~~
/usr/include/c++/6/bits/range_access.h:68:5: note:                 template<class _Container> decltype (__cont.end()) std::end(_Container&)
     end(_Container& __cont) -> decltype(__cont.end())
     ^~~
In file included from /usr/include/c++/6/bits/range_access.h:36:0,
                 from /usr/include/c++/6/string:51,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/initializer_list:99:5: note:                 template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)
     end(initializer_list<_Tp> __ils) noexcept
     ^~~
/in/foo.cc:69:17: error: reference to 'end' is ambiguous
      if(ans>dis[end]+e[i].w)
                 ^~~
/in/foo.cc:6:25: note: candidates are: int end
 int n,m,x,y,z,c=0,start,end,ans=0x7fffffff;
                         ^~~
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/range_access.h:97:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::end(_Tp (&)[_Nm])
     end(_Tp (&__arr)[_Nm])
     ^~~
/usr/include/c++/6/bits/range_access.h:78:5: note:                 template<class _Container> decltype (__cont.end()) std::end(const _Container&)
     end(const _Container& __cont) -> decltype(__cont.end())
     ^~~
/usr/include/c++/6/bits/range_access.h:68:5: note:                 template<class _Container> decltype (__cont.end()) std::end(_Container&)
     end(_Container& __cont) -> decltype(__cont.end())
     ^~~
In file included from /usr/include/c++/6/bits/range_access.h:36:0,
                 from /usr/include/c++/6/string:51,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/initializer_list:99:5: note:                 template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)
     end(initializer_list<_Tp> __ils) noexcept
     ^~~
/in/foo.cc:70:14: error: reference to 'end' is ambiguous
      ans=dis[end]+e[i].w;//从start到end点的最短距离加上该条边的长度 
              ^~~
/in/foo.cc:6:25: note: candidates are: int end
 int n,m,x,y,z,c=0,start,end,ans=0x7fffffff;
                         ^~~
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/range_access.h:97:5: note: