View Compilation Error

0_0_29443911_22280.cpp: In function 'std::vector<int> solve()':
0_0_29443911_22280.cpp:36:32: error: 'strchr' was not declared in this scope
         int o = strchr(op, s[i]) - op;
                                ^
0_0_29443911_22280.cpp: In function 'int main()':
0_0_29443911_22280.cpp:64:41: error: '__gcd' was not declared in this scope
             ans = ans / __gcd(ans, cycle) * cycle;
                                         ^