foo.cc: In function 'void Sort(std::vector<int>&)':
foo.cc:10:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |     for(int i=0;i<M.size()-1;i++)
      |                 ~^~~~~~~~~~~
foo.cc:16:21: warning: unused variable 'tmp' [-Wunused-variable]
   16 |                 int tmp=M[j];
      |                     ^~~
foo.cc: In function 'long long int Sum(std::vector<int>)':
foo.cc:66:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for(int i=0;i<M.size();i++)
      |                 ~^~~~~~~~~

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