Runtime Error
/in/foo.cc: In function 'void dfs(int)': /in/foo.cc:14:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<tre[x].size();i++) ~^~~~~~~~~~~~~~ /in/foo.cc:13:6: warning: unused variable 'sum' [-Wunused-variable] int sum=tre[x].size(); ^~~