/in/foo.cc: In function 'void DFS1(int)':
/in/foo.cc:39:18: 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 DFS2(int, int)':
/in/foo.cc:50:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int k=0;k<gt[i].size();k++)
                 ~^~~~~~~~~~~~~
/in/foo.cc: In function 'void solve()':
/in/foo.cc:80:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int k=0;k<g[i].size();k++)
                 ~^~~~~~~~~~~~