Language: C++

#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
typedef long long ll;
#define _GLIBCXX_DEBUG
typedef vector<int> vec;
typedef vector<ll> lvec;
typedef vector<char> cvec;
typedef vector<double> dvec;
typedef pair<ll, ll> LP;
typedef tuple<ll, ll, ll> LT;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;
#define fs first
#define sc second
int main()	{
  int n;
  cin>>n;
  string s;
  vector<pair<string,int>>dic;
  int mx=0;
  rep(i,n){
    cin>>s;
    dic[s]++;
    mx=max(dic[s],mx);
  }
  sort(all(dic));
  for(auto p:dic){
    if(p.sc==mx)
      cout<<p.fs<<endl;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:26:8: error: no match for 'operator[]' (operand types are 'std::vector<std::pair<std::__cxx11::basic_string<char>, int> >' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   26 |     dic[s]++;
      |        ^
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_vector.h:1128:7: note: candidate: 'std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = std::pair<std::__cxx11::basic_string<char>, int>; _Alloc = std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >; reference = std::pair<std::__cxx11::basic_string<char>, int>&; size_type = long unsigned int]'
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1128:28: note:   no known conversion for argument 1 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'std::vector<std::pair<std::__cxx11::basic_string<char>, int> >::size_type' {aka 'long unsigned int'}
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:1147:7: note: candidate: 'std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = std::pair<std::__cxx11::basic_string<char>, int>; _Alloc = std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >; const_reference = const std::pair<std::__cxx11::basic_string<char>, int>&; size_type = long unsigned int]'
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1147:28: note:   no known conversion for argument 1 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'std::vector<std::pair<std::__cxx11::basic_string<char>, int> >::size_type' {aka 'long unsigned int'}
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
a.cc:27:15: error: no match for 'operator[]' (operand types are 'std::vector<std::pair<std::__cxx11::basic_string<char>, int> >' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   27 |     mx=max(dic[s],mx);
      |               ^
/usr/include/c++/14/bits/stl_vector.h:1128:7: note: candidate: 'std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = std::pair<std::__cxx11::basic_string<char>, int>; _Alloc = std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >; reference = std::pair<std::__cxx11::basic_string<char>, int>&; size_type = long unsigned int]'
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1128:28: note:   no known conversion for argument 1 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'std::vector<std::pair<std::__cxx11::basic_string<char>, int> >::size_type' {aka 'long unsigned int'}
 1128 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:1147:7: note: candidate: 'std::vector<_Tp, _Alloc>::const_reference std::vector<_Tp, _Alloc>::operator[](size_type) const [with _Tp = std::pair<std::__cxx11::basic_string<char>, int>; _Alloc = std::allocator<std::pair<std::__cxx11::basic_string<char>, int> >; const_reference = const std::pair<std::__cxx11::basic_string<char>, int>&; size_type = long unsigned int]'
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1147:28: note:   no known conversion for argument 1 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'std::vector<std::pair<std::__cxx11::basic_string<char>, int> >::size_type' {aka 'long unsigned int'}
 1147 |       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
      |                  ~~~~~~~~~~^~~