Compilare: user.cpp: In function ‘double sol()’: user.cpp:29:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); ++i) { ^ user.cpp:30:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = i + 1; j < v.size(); ++j) { ^ user.cpp:37:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < v.size(); ++k) { ^ user.cpp:63:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (K - free <= pdistances.size()) { ^ user.cpp:66:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (K - free <= ndistances.size()) { ^