Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:30:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ve[x].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:63:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<ve[i].size();j++) ^ user.cpp: In function ‘bool in(int, int)’: user.cpp:26:1: warning: control reaches end of non-void function [-Wreturn-type] } ^