Compilare: user.cpp: In function ‘int main()’: user.cpp:25:72: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( !st.empty() && x > st.top() && st.size() + n - i - 1 >= m ) { ^ user.cpp:26:78: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( !st.empty() && x > st.top() && st.size() + n - i - 1 >= m ) { ^ user.cpp:31:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if ( st.size() < m ) st.push( x ); ^