See Quick.java (Links to an external site.) from our textbook. On an input of size N, the expected "extra space" used is O(lg N). This space is in the runtime stack (also called the "call stack"), where we keep track of the recursive sort calls. The recursion reaches an expected maximum depth of Olg N), and each active call takes a constant number of bytes in the stack. However, if we are unlucky, each pivot could be chosen badly: always the min or max value. In that case, we would get stack depth N, and we would use order N extra space in the stack. If N is large, this can lead to a "stack overflow" error. In a first attempt to reduce the stack usage, we replace the given sort method with this version: private static void sort (Comparable[] a, int lo, int hi) { while (lo