Language: C++

#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main(){
  int n, i;
  cin >> n;
  char w[n][120];
  for(i=0; i<n; i++)
    cin >> w[i];
  for(i=0; i<n-1; i++)
    if(w[i][strlen(w[i])-1]!=w[i+1][0]){
      cout << "No";
      return 0;
    }
  sort(w, w+n);
  for(i=0; i<n-1; i++)
    if(strcmp(w[i], w[i+1])==0){
      cout << "No";
      return 0;
    }
  cout << "Yes";
  return 0;
}

Compiler output:
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_algo.h: In instantiation of 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:1817:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1817 |           std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1908:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1908 |           std::__final_insertion_sort(__first, __last, __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = char (*)[120]]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:16:7:   required from here
   16 |   sort(w, w+n);
      |   ~~~~^~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1780:17: error: array must be initialized with a brace-enclosed initializer
 1780 |                 __val = _GLIBCXX_MOVE(*__i);
      |                 ^~~~~
/usr/include/c++/14/bits/stl_algo.h:1782:24: error: invalid array assignment
 1782 |               *__first = _GLIBCXX_MOVE(__val);
      |                        ^
In file included from /usr/include/c++/14/bits/stl_algo.h:61:
/usr/include/c++/14/bits/stl_heap.h: In instantiation of 'void std::__make_heap(_RandomAccessIterator, _RandomAccessIterator, _Compare&) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:1593:23:   required from 'void std::__heap_select(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1593 |       std::__make_heap(__first, __middle, __comp);
      |       ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1868:25:   required from 'void std::__partial_sort(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1868 |       std::__heap_select(__first, __middle, __last, __comp);
      |       ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1884:27:   required from 'void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = char (*)[120]; _Size = long int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1884 |               std::__partial_sort(__first, __last, __last, __comp);
      |               ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1905:25:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1905 |           std::__introsort_loop(__first, __last,
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1907 |                                 __comp);
      |                                 ~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = char (*)[120]]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:16:7:   required from here
   16 |   sort(w, w+n);
      |   ~~~~^~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:355:22: error: array must be initialized with a brace-enclosed initializer
  355 |           _ValueType __value = _GLIBCXX_MOVE(*(__first + __parent));
      |                      ^~~~~~~
/usr/include/c++/14/bits/stl_heap.h: In instantiation of 'void std::__pop_heap(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare&) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]':
/usr/include/c++/14/bits/stl_algo.h:1596:19:   required from 'void std::__heap_select(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1596 |           std::__pop_heap(__first, __middle, __i, __comp);
      |           ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1868:25:   required from 'void std::__partial_sort(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1868 |       std::__heap_select(__first, __middle, __last, __comp);
      |       ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1884:27:   required from 'void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = char (*)[120]; _Size = long int; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1884 |               std::__partial_sort(__first, __last, __last, __comp);
      |               ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1905:25:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = char (*)[120]; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
 1905 |           std::__introsort_loop(__first, __last,
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
 1906 |                                 std::__lg(__last - __first) * 2,
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1907 |                                 __comp);
      |                                 ~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4772:18:   required from 'void std::sort(_RAIter, _RAIter) [with _RAIter = char (*)[120]]'
 4772 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:16:7:   required from here
   16 |   sort(w, w+n);
      |   ~~~~^~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:262:18: error: array must be initialized with a brace-enclosed initializer
  262 |       _ValueType __value = _GLIBCXX_MOVE(*__result);
      |                  ^~~~~~~
/usr/include/c++/14/bits/stl_heap.h:263:17: error: invalid array assignment
  263 |       *__result = _GLIBCXX_MOVE(*__first);
      |                 ^