foo.cc: In function 'int main()':
foo.cc:12:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |                 for(int j=0;j<a.size();j++){
      |                             ~^~~~~~~~~
foo.cc:25:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |         for(int i=0;i!=a.size();i++){
      |                     ~^~~~~~~~~~

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