Do you mean L&S undeclared or CoE undeclared? CoE undeclared is highly competitive for admission, since CoE undeclared can choose any CoE major later.
L&S undeclared is generally less competitive than most CoE majors. However, L&S students must earn a 3.3 GPA in CS 61A, 61B, 70 to enter the L&S CS major (about half of students in those courses earn B+ or higher grades). Changing into EECS from outside of CoE is not allowed any more due to how full EECS is.