/in/foo.cc: In function 'void DFS(int, int, int)':
/in/foo.cc:13:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int k=0;k<g[i].size();k++){
              ~^~~~~~~~~~~~
/in/foo.cc: In function 'void DFSx(int)':
/in/foo.cc:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int k=0;k<g[i].size();k++){
              ~^~~~~~~~~~~~