answer.code: In function ‘void init(int, const std::vector<int>&)’:
answer.code:12:47: error: ‘gcd’ was not declared in this scope
   12 |     for (int i = base; i >= 1; -- i) seg[i] = gcd(seg[i << 1], seg[i << 1 | 1]);
      |                                               ^~~
answer.code: In function ‘void modify(int, int)’:
answer.code:16:60: error: ‘gcd’ was not declared in this scope
   16 |     for (int i = (pos + base) >> 1; i >= 1; -- i) seg[i] = gcd(seg[i << 1], seg[i << 1 | 1]);
      |                                                            ^~~
answer.code: In function ‘int query(int, int)’:
answer.code:22:27: error: ‘gcd’ was not declared in this scope
   22 |         if (~l & 1) ans = gcd(ans, seg[l ^ 1]);
      |                           ^~~
answer.code:23:26: error: ‘gcd’ was not declared in this scope
   23 |         if (r & 1) ans = gcd(ans, seg[r ^ 1]);
      |                          ^~~
answer.code: In lambda function:
answer.code:52:14: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   52 |         auto [l, r] = *itr;
      |              ^
answer.code:69:18: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   69 |             auto [L, R] = *t1;
      |                  ^
answer.code:79:18: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   79 |             auto [L1, R1] = *t1;
      |                  ^
answer.code:80:18: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   80 |             auto [L2, R2] = *t2;
      |                  ^
answer.code: In lambda function:
answer.code:89:14: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   89 |         auto [l, r] = *prev(st.end());
      |              ^