Compilare: main.cpp: In function 'bool OK(long long unsigned int)': main.cpp:22:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1; i<(1<<pr); ++i) { ~^~~~~~~~ main.cpp:24:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; (1<<j)<=i; ++j) { ~~~~~~^~~