Compilare: user.cpp: In function ‘int main()’: user.cpp:25:63: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (!st.empty() && c > st.back() && st.size() + n - k >= m) ^ user.cpp:15:7: warning: unused variable ‘s’ [-Wunused-variable] char s[1000000], c; ^ user.cpp:17:7: warning: unused variable ‘cur’ [-Wunused-variable] char cur; ^