Eroare de compilare: user.cpp: In function ‘void df(int, int)’: user.cpp:47:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int it=0;it<a[k].size();++it) ^ user.cpp: In function ‘int main()’: user.cpp:10:11: error: ‘first’ was not declared in this scope #define f first ^ user.cpp:68:5: note: in expansion of macro ‘f’ f>>n>>m; ^ user.cpp:84:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();++i) ^ user.cpp:86:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<sol[i].size();++j) ^