foo.cc: In member function 'bool BigIntArray::Cmp(std::string&, std::string&)':
foo.cc:27:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |             for(int i = 0; i<A.size(); i++)
      |                            ~^~~~~~~~~

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