Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:24:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < v[x].size() ; ++i) ~~^~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:43:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0 ; j < v[topSort[i]].size() ; ++j) { ~~^~~~~~~~~~~~~~~~~~~~~~