foo.cc: In function 'int main()':
foo.cc:9:24: error: reference to 'begin' is ambiguous
    9 |     scanf("%d%d%d",&n,&begin,&maxlevel);
      |                        ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:95,
                 from foo.cc:1:
/usr/include/c++/9/valarray:1224:5: note: candidates are: 'template<class _Tp> const _Tp* std::begin(const std::valarray<_Tp>&)'
 1224 |     begin(const valarray<_Tp>& __va)
      |     ^~~~~
/usr/include/c++/9/valarray:1214:5: note:                 'template<class _Tp> _Tp* std::begin(std::valarray<_Tp>&)'
 1214 |     begin(valarray<_Tp>& __va)
      |     ^~~~~
In file included from /usr/include/c++/9/string:54,
                 from /usr/include/c++/9/bits/locale_classes.h:40,
                 from /usr/include/c++/9/bits/ios_base.h:41,
                 from /usr/include/c++/9/ios:42,
                 from /usr/include/c++/9/istream:38,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from foo.cc:1:
/usr/include/c++/9/bits/range_access.h:87:5: note:                 'template<class _Tp, long unsigned int _Nm> _Tp* std::begin(_Tp (&)[_Nm])'
   87 |     begin(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~~~
/usr/include/c++/9/bits/range_access.h:58:5: note:                 'template<class _Container> decltype (__cont.begin()) std::begin(const _Container&)'
   58 |     begin(const _Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
/usr/include/c++/9/bits/range_access.h:48:5: note:                 'template<class _Container> decltype (__cont.begin()) std::begin(_Container&)'
   48 |     begin(_Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
In file included from /usr/include/c++/9/bits/range_access.h:36,
                 from /usr/include/c++/9/string:54,
                 from /usr/include/c++/9/bits/locale_classes.h:40,
                 from /usr/include/c++/9/bits/ios_base.h:41,
                 from /usr/include/c++/9/ios:42,
                 from /usr/include/c++/9/istream:38,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from foo.cc:1:
/usr/include/c++/9/initializer_list:89:5: note:                 'template<class _Tp> constexpr const _Tp* std::begin(std::initializer_list<_Tp>)'
   89 |     begin(initializer_list<_Tp> __ils) noexcept
      |     ^~~~~
foo.cc:3:7: note:                 'int begin'
    3 | int n,begin,maxlevel;
      |       ^~~~~
foo.cc:10:10: error: reference to 'begin' is ambiguous
   10 |     f[0][begin]=1;
      |          ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:95,
                 from foo.cc:1:
/usr/include/c++/9/valarray:1224:5: note: candidates are: 'template<class _Tp> const _Tp* std::begin(const std::valarray<_Tp>&)'
 1224 |     begin(const valarray<_Tp>& __va)
      |     ^~~~~
/usr/include/c++/9/valarray:1214:5: note:                 'template<class _Tp> _Tp* std::begin(std::valarray<_Tp>&)'
 1214 |     begin(valarray<_Tp>& __va)
      |     ^~~~~
In file included from /usr/include/c++/9/string:54,
                 from /usr/include/c++/9/bits/locale_classes.h:40,
                 from /usr/include/c++/9/bits/ios_base.h:41,
                 from /usr/include/c++/9/ios:42,
                 from /usr/include/c++/9/istream:38,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from foo.cc:1:
/usr/include/c++/9/bits/range_access.h:87:5: note:                 'template<class _Tp, long unsigned int _Nm> _Tp* std::begin(_Tp (&)[_Nm])'
   87 |     begin(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~~~
/usr/include/c++/9/bits/range_access.h:58:5: note:                 'template<class _Container> decltype (__cont.begin()) std::begin(const _Container&)'
   58 |     begin(const _Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
/usr/include/c++/9/bits/range_access.h:48:5: note:                 'template<class _Container> decltype (__cont.begin()) std::begin(_Container&)'
   48 |     begin(_Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
In file included from /usr/include/c++/9/bits/range_access.h:36,
                 from /usr/include/c++/9/string:54,
                 from /usr/include/c++/9/bits/locale_classes.h:40,
                 from /usr/include/c++/9/bits/ios_base.h:41,
                 from /usr/include/c++/9/ios:42,
                 from /usr/include/c++/9/istream:38,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from foo.cc:1:
/usr/include/c++/9/initializer_list:89:5: note:                 'template<class _Tp> constexpr const _Tp* std::begin(std::initializer_list<_Tp>)'
   89 |     begin(initializer_list<_Tp> __ils) noexcept
      |     ^~~~~
foo.cc:3:7: note:                 'int begin'
    3 | int n,begin,maxlevel;
      |       ^~~~~
foo.cc:13:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |         scanf("%d",&a[i]);
      |         ~~~~~^~~~~~~~~~~~

Found 11 testcases.
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