Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  int N;
  cin >> N;
  vector<pair<int, int>> p(N);
  for (int i = 0; i < N; i++) {
    string a;
    int b;
    cin >> a >> b;
    p.at(i) = make_pair(a, b);  // b, a の順でペアにする
  }

  sort(p.begin(), p.end());

  for (int i = 0; i < N; i++) {
    int a, b;
    tie(a, b) = p.at(i);  // b, a の順であることに注意
    cout << a << " " << b << endl;
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:12:29: error: no match for 'operator=' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<std::pair<int, int> >, std::pair<int, int> >::value_type' {aka 'std::pair<int, int>'} and 'std::pair<std::__cxx11::basic_string<char>, int>')
   12 |     p.at(i) = make_pair(a, b);  // b, a の順でペアにする
      |                             ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_pair.h:946:9: note: candidate: 'template<class _U1, class _U2> typename std::enable_if<std::__and_<std::is_assignable<_T1&, const _U1&>, std::is_assignable<_T2&, const _U2&> >::value, std::pair<_T1, _T2>&>::type std::pair<_T1, _T2>::operator=(const std::pair<_U1, _U2>&) [with _U2 = _U1; _T1 = int; _T2 = int]'
  946 |         operator=(const pair<_U1, _U2>& __p)
      |         ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:946:9: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_pair.h: In substitution of 'template<class _U1, class _U2> typename std::enable_if<std::__and_<std::is_assignable<int&, const _U1&>, std::is_assignable<int&, const _U2&> >::value, std::pair<int, int>&>::type std::pair<int, int>::operator=(const std::pair<_T1, _T2>&) [with _U1 = std::__cxx11::basic_string<char>; _U2 = int]':
a.cc:12:29:   required from here
   12 |     p.at(i) = make_pair(a, b);  // b, a の順でペアにする
      |                             ^
/usr/include/c++/14/bits/stl_pair.h:946:9: error: no type named 'type' in 'struct std::enable_if<false, std::pair<int, int>&>'
  946 |         operator=(const pair<_U1, _U2>& __p)
      |         ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:957:9: note: candidate: 'template<class _U1, class _U2> typename std::enable_if<std::__and_<std::is_assignable<_T1&, _U1&&>, std::is_assignable<_T2&, _U2&&> >::value, std::pair<_T1, _T2>&>::type std::pair<_T1, _T2>::operator=(std::pair<_U1, _U2>&&) [with _U2 = _U1; _T1 = int; _T2 = int]'
  957 |         operator=(pair<_U1, _U2>&& __p)
      |         ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:957:9: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_pair.h: In substitution of 'template<class _U1, class _U2> typename std::enable_if<std::__and_<std::is_assignable<int&, _U1&&>, std::is_assignable<int&, _U2&&> >::value, std::pair<int, int>&>::type std::pair<int, int>::operator=(std::pair<_T1, _T2>&&) [with _U1 = std::__cxx11::basic_string<char>; _U2 = int]':
a.cc:12:29:   required from here
   12 |     p.at(i) = make_pair(a, b);  // b, a の順でペアにする
      |                             ^
/usr/include/c++/14/bits/stl_pair.h:957:9: error: no type named 'type' in 'struct std::enable_if<false, std::pair<int, int>&>'
  957 |         operator=(pair<_U1, _U2>&& __p)
      |         ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:921:7: note: candidate: 'std::pair<_T1, _T2>& std::pair<_T1, _T2>::operator=(std::__conditional_t<((bool)std::__and_<std::is_copy_assignable<_T1>, std::is_copy_assignable<_T2> >::value), const std::pair<_T1, _T2>&, const std::__nonesuch&>) [with _T1 = int; _T2 = int; std::__conditional_t<((bool)std::__and_<std::is_copy_assignable<_T1>, std::is_copy_assignable<_T2> >::value), const std::pair<_T1, _T2>&, const std::__nonesuch&> = const std::pair<int, int>&]'
  921 |       operator=(__conditional_t<__and_<is_copy_assignable<_T1>,
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:923:65: note:   no known conversion for argument 1 from 'std::pair<std::__cxx11::basic_string<char>, int>' to 'std::__conditional_t<true, const std::pair<int, int>&, const std::__nonesuch&>' {aka 'const std::pair<int, int>&'}
  921 |       operator=(__conditional_t<__and_<is_copy_assignable<_T1>,
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  922 |                                        is_copy_assignable<_T2>>::value,
      |                                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  923 |                                 const pair&, const __nonesuch&> __p)
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_pair.h:931:7: note: candidate: 'std::pair<_T1, _T2>& std::pair<_T1, _T2>::operator=(std::__conditional_t<((bool)std::__and_<std::is_move_assignable<_Tp>, std::is_move_assignable<_T2> >::value), std::pair<_T1, _T2>&&, std::__nonesuch&&>) [with _T1 = int; _T2 = int; std::__conditional_t<((bool)std::__and_<std::is_move_assignable<_Tp>, std::is_move_assignable<_T2> >::value), std::pair<_T1, _T2>&&, std::__nonesuch&&> = std::pair<int, int>&&]'
  931 |       operator=(__conditional_t<__and_<is_move_assignable<_T1>,
      |       ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:933:55: note:   no known conversion for argument 1 from 'std::pair<std::__cxx11::basic_string<char>, int>' to 'std::__conditional_t<true, std::pair<int, int>&&, std::__nonesuch&&>' {aka 'std::pair<int, int>&&'}
  931 |       operator=(__conditional_t<__and_<is_move_assignable<_T1>,
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  932 |                                        is_move_assignable<_T2>>::value,
      |                                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  933 |                                 pair&&, __nonesuch&&> __p)
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~