/in/foo.cc: In function 'int kth(int, int)':
/in/foo.cc:44:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(dep[u]<k) return 0; if(!k) return u;
  ^~
/in/foo.cc:44:25: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
  if(dep[u]<k) return 0; if(!k) return u;
                         ^~
/in/foo.cc: In function 'int main()':
/in/foo.cc:59:46: warning: operation on 'u' may be undefined [-Wsequence-point]
   while(l<len[i] && u) ++l,anc[u].push_back(u=fa[u][0]);
                                             ~^~~~~~~~~
/in/foo.cc:61:42: warning: operation on 'u' may be undefined [-Wsequence-point]
   while(l<len[i]) ++l,hson[u].push_back(u=son[u]);
                                         ~^~~~~~~
/in/foo.cc: In function 'int kth(int, int)':
/in/foo.cc:49:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^