foo.cc: In function 'int main()':
foo.cc:18:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |  for(int i=0;i<v.size();i++)
      |              ~^~~~~~~~~
foo.cc:19:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |   for(int j=i+1;j<v.size();j++)
      |                 ~^~~~~~~~~
foo.cc:31:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |  for(int i=0;i<v.size();i++)
      |              ~^~~~~~~~~

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