SELF-CHECK

1. Trace the execution of quicksort on the following array, assuming that the first item in each subarray is the pivot value. Show the values of first and last for each recursive call and the array elements after returning from each call. Also, show the value of pivot during each call and the value returned through pivIndex. How many times is sort called, and how many times is partition called?55 50 10 40 80 90 60 100 70 80 20 50 22
2. Redo Question 1 above using the revised partition algorithm, which does a preliminary sort of three elements and selects their median as the pivot value.
3. Explain why the condition (down > first) is not necessary in the loop that decrements down.