View Compilation Error

0_0_38966785_8612.cpp: In function 'int find_valid_pairs(int, int, int)':
0_0_38966785_8612.cpp:28:16: error: 'gcd' cannot be used as a function
   28 |   int gcd = gcd(a, b);
      |             ~~~^~~~~~
0_0_38966785_8612.cpp:33:34: error: no match for call to '(std::vector<int>) (int)'
   33 |   vector<int> divisors = divisors(c / gcd);
      |                          ~~~~~~~~^~~~~~~~~