Compilare: main.cpp: In function 'void topsort(int)': main.cpp:19:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i< l[nod].size(); i++) ~^~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:30:18: warning: unused variable 'aux' [-Wunused-variable] int i, x, y, aux; ^~~ main.cpp:31:10: warning: unused variable 'k' [-Wunused-variable] char k; ^