/in/foo.cc: In member function 'void BigInt::solve()':
/in/foo.cc:61:25: error: 'memset' was not declared in this scope
   61 |                         memset(ans,0,10000);
      |                         ^~~~~~
/in/foo.cc:5:1: note: 'memset' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    4 | #include<cmath>
  +++ |+#include <cstring>
    5 | using namespace std;