foo.cc: In function 'int main()':
foo.cc:56:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   for(int i=0; i<aa.size(); i++)
      |                ~^~~~~~~~~~
foo.cc:64:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |   for(int i=0; i<bb.size(); i++)
      |                ~^~~~~~~~~~

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