Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int N;
  cin >> N;
  vector<int> A(N);
  vector<vector<int>> B(N,vector<int>(N));
  
  for(int i = 0; i < N, i++) {
    cin >> A.at(i);
  }
  for(int i = 0; i < N, i++) {
    for(int j = 0; j < N, j++) {
      B.at(i).at(j) = A.at(j);
    }
  }
  B.at(0).at(0) = A.at(N)
  for(int i = 1; i < N, i++) {
    B.at(i).at(i) = A.at(i-1);
  }
  
  for(int i = 0; i < N, i++) {
    for(int j = 0; j < N-1, j++) {
      B.at(i).at(j+1) = gcd(B.at(i).at(j), B.at(i).at(j+1));
    }
  }
  int ans = 0;
  for(int i = 0; i < N, i++) {
    ans = max(ans,B.at(N-1));
  }
  cout << ans << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:28: error: expected ';' before ')' token
   10 |   for(int i = 0; i < N, i++) {
      |                            ^
      |                            ;
a.cc:13:28: error: expected ';' before ')' token
   13 |   for(int i = 0; i < N, i++) {
      |                            ^
      |                            ;
a.cc:14:30: error: expected ';' before ')' token
   14 |     for(int j = 0; j < N, j++) {
      |                              ^
      |                              ;
a.cc:18:26: error: expected ';' before 'for'
   18 |   B.at(0).at(0) = A.at(N)
      |                          ^
      |                          ;
   19 |   for(int i = 1; i < N, i++) {
      |   ~~~                     
a.cc:19:18: error: 'i' was not declared in this scope
   19 |   for(int i = 1; i < N, i++) {
      |                  ^
a.cc:23:28: error: expected ';' before ')' token
   23 |   for(int i = 0; i < N, i++) {
      |                            ^
      |                            ;
a.cc:24:32: error: expected ';' before ')' token
   24 |     for(int j = 0; j < N-1, j++) {
      |                                ^
      |                                ;
a.cc:29:28: error: expected ';' before ')' token
   29 |   for(int i = 0; i < N, i++) {
      |                            ^
      |                            ;
a.cc:30:14: error: no matching function for call to 'max(int&, __gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type&)'
   30 |     ans = max(ans,B.at(N-1));
      |           ~~~^~~~~~~~~~~~~~~
In file included 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_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:30:14: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type' {aka 'std::vector<int>'})
   30 |     ans = max(ans,B.at(N-1));
      |           ~~~^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:30:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   30 |     ans = max(ans,B.at(N-1));
      |           ~~~^~~~~~~~~~~~~~~