Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:36:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < l[nod].size(); i++) { ^ user.cpp: In function ‘void dfs2(int, int)’: user.cpp:59:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0;i < l[nod].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:110:20: warning: integer overflow in expression [-Woverflow] dfs2 (1,-(1<<31)); ^