Compilare: main.cpp: In function 'void solve()': main.cpp:31:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (dq.size() >= k && a[dq.back()] - a[dq.front() - 1] > smax) { ~~~~~~~~~~^~~~ main.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (dq.size() > k && a[dq.back()] - a[dq.front()] >= a[dq.back()] - a[dq.front() - 1]) ~~~~~~~~~~^~~