Compilare: user.cpp: In function ‘int main()’: user.cpp:26:73: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( !st.empty() && x > st.back() && st.size() + n - i - 1 >= m ) { ^ user.cpp:27:79: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( !st.empty() && x > st.back() && st.size() + n - i - 1 >= m ) { ^ user.cpp:32:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if ( st.size() < m ) st.push_back( x ); ^ user.cpp:34:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( st.size() + n - i - 1 == m ) { ^