/in/foo.cc: In function 'void bfs(int)':
/in/foo.cc:22:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<an[now].size();++i)
               ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:44:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<cn[i].size();++j)
              ~^~~~~~~~~~~~~
/in/foo.cc:44:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int j=0;j<cn[i].size();++j)
  ^~~
/in/foo.cc:50:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   bfs(t);
   ^~~