Compilare: main.cpp: In function 'int dfs(int, int)': main.cpp:12:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<L[nod].size(); ++i) ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:36:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ans.size(); ++i) ~^~~~~~~~~~~ main.cpp:32:9: warning: unused variable 'ok' [-Wunused-variable] int ok=dfs(1,-1); ^~