/in/foo.cc: In function 'int main()':
/in/foo.cc:21:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<=s.length();i++)
              ~^~~~~~~~~~~~
/in/foo.cc:30:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<v.size();i++)
              ~^~~~~~~~~
/in/foo.cc:43:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.length();i++) cout<<ans[i]<<" ";
              ~^~~~~~~~~~~