/in/foo.cc: In function 'void search(int, int, int)':
/in/foo.cc:18:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=fa+1;i<front.size();++i) {
                 ~^~~~~~~~~~~~~
/in/foo.cc:31:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=fa+1;i<front.size();++i) {
                 ~^~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:52:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<front.size();++i) {
              ~^~~~~~~~~~~~~