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+11 votes

Quick-sort is run on two inputs shown below to sort in ascending order taking first element as pivot

  1. $1, 2, 3, \dots n$
  2. $n, n-1, n-2, \dots, 2, 1$

Let $C_1$ and $C_2$ be the number of comparisons made for the inputs (i) and (ii) respectively. Then, 

  1. $C_1 < C_2$
  2. $C_1 > C_2$
  3. $C_1 = C_2$
  4. we cannot say anything for arbitrary $n$


asked in Algorithms by Veteran (67.5k points)
retagged by | 773 views
Notice --> 'Comparison' and 'Swap' may be different.

1 Answer

+16 votes
Best answer

both are the worst cases of quick sort. (assuming pivot is either first or last element)

  1. is sorted in ascending order.
  2. is sorted in descending order.
answered by Veteran (19.3k points)
edited ago by
Does not it depend on the pivot chosen?
yes, it should. I guess it is missing in question.
explain anyone ... specifically abt the pivot element......

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