View Compilation Error

0_0_36364703_14295.cpp: In function 'void solve()':
0_0_36364703_14295.cpp:21:17: error: 'gcd' is not a member of 'std'
         int g = std::gcd(x, y);
                 ^
0_0_36364703_14295.cpp:36:51: error: missing template arguments before '(' token
     std::sort(cnt.begin(), cnt.end(), std::greater());
                                                   ^