/in/foo.cc: In function 'bool equals(std::vector<int>, std::vector<int>)':
/in/foo.cc:6:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0;i<a.size();i++){
                ~^~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:36:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0;i<coins.size();i++){
                ~^~~~~~~~~~~~~