Language: C++

#include <bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(false); cin.tie(0);
#define FOR(i,s,n) for(int i = s; i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(n) (n).begin(), (n).end()
#define RALL(n) (n).rbegin(), (n).rend()
#define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
using ll = long long;
using ull = unsigned long long;

int main(void)
{
    IOS
    int n;
    cin >> n;

    bool ans = true;
    bool down = false;
    int prev = 0;
    REP(i,n) {
        int x;
        cin >> x;
        if (x  == prev-1) {
            if (down) {
                ans = false;
            } else {
                down = true;
            }
        } else if (x < prev) {
            ans = false;

        } else if (x > prev) {
            down = false;
        }
        
        prev = x;
        
    }

    YESNO(ans)

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:23: error: no match for 'operator>>' (operand types are 'std::ostream' {aka 'std::basic_ostream<char>'} and 'const char*')
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                  ~~~~ ^~ ~~~~~~~~~~~~~~~~~~~
      |                  |             |
      |                  |             const char*
      |                  std::ostream {aka std::basic_ostream<char>}
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41,
                 from a.cc:1:
/usr/include/c++/14/cstddef:131:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator>>(byte, _IntegerType)'
  131 |     operator>>(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/14/cstddef:131:5: note:   template argument deduction/substitution failed:
a.cc:8:18: note:   cannot convert 'std::cout' (type 'std::ostream' {aka 'std::basic_ostream<char>'}) to type 'std::byte'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                  ^~~~
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
In file included from /usr/include/c++/14/string:55,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/basic_string.tcc:835:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
  835 |     operator>>(basic_istream<_CharT, _Traits>& __in,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.tcc:835:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/bitset:1597:5: note: candidate: 'template<class _CharT, class _Traits, long unsigned int _Nb> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, bitset<_Nb>&)'
 1597 |     operator>>(std::basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1597:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
In file included from /usr/include/c++/14/istream:1109,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/bits/istream.tcc:978:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _CharT&)'
  978 |     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
      |     ^~~~~~~~
/usr/include/c++/14/bits/istream.tcc:978:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/istream:849:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, unsigned char&)'
  849 |     operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
      |     ^~~~~~~~
/usr/include/c++/14/istream:849:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/istream:854:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, signed char&)'
  854 |     operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
      |     ^~~~~~~~
/usr/include/c++/14/istream:854:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/istream:896:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _CharT*)'
  896 |     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:896:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/istream:939:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, unsigned char*)'
  939 |     operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:939:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/istream:945:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, signed char*)'
  945 |     operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:945:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/istream:1099:5: note: candidate: 'template<class _Istream, class _Tp> _Istream&& std::operator>>(_Istream&&, _Tp&&)'
 1099 |     operator>>(_Istream&& __is, _Tp&& __x)
      |     ^~~~~~~~
/usr/include/c++/14/istream:1099:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/istream: In substitution of 'template<class _Istream, class _Tp> _Istream&& std::operator>>(_Istream&&, _Tp&&) [with _Istream = std::basic_ostream<char>&; _Tp = const char*]':
a.cc:41:5:   required from here
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
/usr/include/c++/14/istream:1099:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
 1099 |     operator>>(_Istream&& __is, _Tp&& __x)
      |     ^~~~~~~~
/usr/include/c++/14/complex:509:5: note: candidate: 'template<class _Tp, class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, complex<_Tp>&)'
  509 |     operator>>(basic_istream<_CharT, _Traits>& __is, complex<_Tp>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/complex:509:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:143:
/usr/include/c++/14/iomanip:76:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Resetiosflags)'
   76 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Resetiosflags __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:76:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
    8 | #define YESNO(n) cout >> ( (n) ? "Yes":"No") >> endl;
      |                                            ^
a.cc:41:5: note: in expansion of macro 'YESNO'
   41 |     YESNO(ans)
      |     ^~~~~
/usr/include/c++/14/iomanip:106:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Setiosflags)'
  106 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Setiosflags __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:106:5: note:   template argument deduction/substitution failed:
a.cc:8:44: note:   'std::ostream' {aka 'std::basic_ostream<char