Compilare: user.cpp: In function ‘int main()’: user.cpp:91:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < dfs.size() - 1 ; ++ i){ ^ user.cpp:97:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < dfs.size() ; ++ i) ^