foo.cc: In function 'int main()':
foo.cc:27:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |                 for(int j=0;j<vec[i].size();j++){
      |                             ~^~~~~~~~~~~~~~
foo.cc:48:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |                         for(int j=0;j<vec[i].size();j++){
      |                                     ~^~~~~~~~~~~~~~

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