Compilare: main.cpp: In function 'void buildDivs()': main.cpp:25:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<primes.size() && x > 1; ++i) { ~^~~~~~~~~~~~~~ main.cpp: In function 'void calcrecc(long long int, int, int)': main.cpp:34:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (idx >= divs.size()) return; ~~~~^~~~~~~~~~~~~~ main.cpp:35:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=idx; i<divs.size(); ++i) ~^~~~~~~~~~~~