Compilare: user.cpp: In function ‘void calibrate(std::multiset<int>&, std::multiset<int>&, int, int)’: user.cpp:119:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (!P.empty() && S.size() < n){ ^ user.cpp:125:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (!S.empty() && S.size() > n){ ^ user.cpp:134:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (S.size() < n) ^