foo.cc: In function 'int main()':
foo.cc:22:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |  for(i=0; i<a.size(); i++)
      |           ~^~~~~~~~~
foo.cc:35:6: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |  if(i==a.size() &&( l1 != r1 || l2 != r2)) flag = false;
      |     ~^~~~~~~~~~

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