foo.cc: In function 'int main()':
foo.cc:29:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |     for(int i=0;i<alls.size();i++)
      |                 ~^~~~~~~~~~~~
foo.cc:32:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |         for(int j=i+1;j<alls.size();j++)
      |                       ~^~~~~~~~~~~~

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