/in/foo.cc: In function 'int mina()':
/in/foo.cc:7:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<y.size()&&j<y.size()&&k<y.size())
        ~^~~~~~~~~
/in/foo.cc:7:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<y.size()&&j<y.size()&&k<y.size())
                    ~^~~~~~~~~
/in/foo.cc:7:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<y.size()&&j<y.size()&&k<y.size())
                                ~^~~~~~~~~