answer.code: In function ‘int main()’:
answer.code:43:18: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’
   43 |             auto [p, q] = check(zeroes);
      |                  ^
answer.code:53:18: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’
   53 |             auto [p, q] = check(mid);
      |                  ^
answer.code:62:14: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’
   62 |         auto [p, q] = check(from);
      |              ^
answer.code:63:17: error: ‘gcd’ was not declared in this scope
   63 |         int d = gcd(p, q);
      |                 ^~~
answer.code:11:10: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   11 |     scanf("%d", &cases);
      |     ~~~~~^~~~~~~~~~~~~~
answer.code:15:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   15 |         scanf("%d", &n);
      |         ~~~~~^~~~~~~~~~
answer.code:19:18: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   19 |             scanf("%d", &v);
      |             ~~~~~^~~~~~~~~~