Compilare: user.cpp: In function ‘int main()’: user.cpp:60:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < ans.size() ; ++i) ^ user.cpp:64:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0 ; j < ans[i].size() ; ++j) ^ user.cpp: In function ‘int fb(int)’: user.cpp:20:1: warning: control reaches end of non-void function [-Wreturn-type] } ^