Language: C++

#include <bits/stdc++.h>
using namespace std;
int main() {
  int n = 0;
  int q = 0;
  cin >> n;
  vector<int> a(n);
  for(int i = 0; i < n; i++) {
    cin >> a.at(i);
  }
  cin >> q;
  vector<vector<int>> man(q,vector<int>(2));
  for(int i = 0; i < q; i++) {
    cin >> man.at(i).at(0);
    cin >> man.at(i).at(1);
  }
  vector<int> ans(q);
  for(int i = 0; i < q; i++) {
    int sum = 0;
    replace(man.begin(),man.end(),man.at(i).at(0),man.at(i).at(1));
    for(int i = 0; i < n; i++) {
      sum += n;
    }
    ans.at(i) = sum;
    cout << sum << endl;
  }
}


Compiler output:
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algo.h: In instantiation of 'void std::replace(_FIter, _FIter, const _Tp&, const _Tp&) [with _FIter = __gnu_cxx::__normal_iterator<vector<int>*, vector<vector<int> > >; _Tp = int]':
a.cc:20:12:   required from here
   20 |     replace(man.begin(),man.end(),man.at(i).at(0),man.at(i).at(1));
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4293:22: error: no match for 'operator==' (operand types are 'std::vector<int>' and 'const int')
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::pair<_T1, _T2>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::reverse_iterator<_Iterator>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::reverse_iterator<_Iterator>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::move_iterator<_IteratorL>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::move_iterator<_IteratorL>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/c++allocator.h:33,
                 from /usr/include/c++/14/bits/allocator.h:46,
                 from /usr/include/c++/14/string:43,
                 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/new_allocator.h:215:9: note: candidate: 'template<class _Up> bool std::operator==(const __new_allocator<int>&, const __new_allocator<_Tp>&)'
  215 |         operator==(const __new_allocator&, const __new_allocator<_Up>&)
      |         ^~~~~~~~
/usr/include/c++/14/bits/new_allocator.h:215:9: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   mismatched types 'const std::__new_allocator<_Tp>' and 'const int'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181:
/usr/include/c++/14/bits/regex.h:1103:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1103 |     operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1103:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:1199:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1199 |     operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1199:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:1274:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1274 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1274:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:1366:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1366 |     operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1366:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'const int'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:1441:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1441 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1441:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:1534:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1534 |     operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1534:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'const int'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:1613:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1613 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1613:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/regex.h:2186:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator==(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2186 |     operator==(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2186:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/bits/stl_algo.h:4293:22: note:   'std::vector<int>' is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
 4293 |         if (*__first == __old_value)
      |             ~~~~~~~~~^~~~~~~~~~~~~~
In file included from /usr/include/c++/14/unordered_set:41,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:189:
/usr/include/c++/14/bits/unordered_set.h:1827:5: note: candidate: 'template<class _Value1, c