foo.cc: In function 'void doing()':
foo.cc:16:44: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |                         for(long long i=0;i<a.size();i++){
      |                                           ~^~~~~~~~~
foo.cc:24:36: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |                 for(long long i=0;i<rs.size();i++){
      |                                   ~^~~~~~~~~~
foo.cc:30:52: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |                                 for(long long j=i;j<a.size();j++){
      |                                                   ~^~~~~~~~~

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