Compilare: user.cpp: In function ‘int main()’: user.cpp:15:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < m; i++){ ^ user.cpp:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= n; i++) fout << lens[i] << ' '; ^