Multiple choice

Consider the Quicksort algorithm. Suppose there is a procedure for finding a pivot element which splits the list into two sub-lists each of which contains at least one-fifth of the elements. Let T(n) be the number of comparisons required to sort n elements. Then

  1. $T(n) \leq 2T(n/5) + n$
  2. $T(n) \leq T(n/5) + T(4n/5) + n$
  3. $T(n) \leq 2T(4n/5) + n$
  4. $T(n) \leq 2T(n/2) + n$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation