What is the time complexity of adding an element at the beginning of an ArrayList?

Question

Say I have a ArrayList with n element in this array, and I add an element at the beginning:

myArrayList.add(0,\'some value\');

What will be the

Answer 1

• Building the list from scratch and adding lots of elements to the beginning runs in quadratic time: O(n²).
• Adding all elements to the end of the list and then calling Collections.reverse(list) runs in linear time: O(n).