Shell sort is a generalization of insertion sort that allows exchanges of elements far apart in an array. It was created by Donald Shell in 1959 and works by making multiple passes with step sizes to sort subsets of the full list, improving on insertion sort's efficiency. Shell sort breaks the quadratic time barrier of other simple sorts but is still slower than other modern algorithms like quicksort.

1. Presentation:
Topic: Shell Sort
• Course:
Data Structure
Presented by:
Waqar Ashraf
Comsats
University,Punjab,Pakistan.

2. Introduction:
• Founded by Donald Shell and named the sorting algorithm after
himself in 1959.
• 1st algorithm to break the quadratic time barrier but few years later, a
sub quadratic time bound was proven.
• Shell sort works by comparing elements that are distant rather than
adjacent elements in an array or list where adjacent elements are
compared.

3. What is Shell Sort:
• Shell sort is a sorting algorithm. It is an in-place comparison sort and
one of the oldest sorting algorithm. Shell sort is a generalization of
insertion sort that allows the exchange of items that are far apart.
• Shell sort makes multiple passes through a list and sorts a number of
equally sized sets using the insertion sort.
• Shell sort improves on the efficiency of insertion sort by quickly
shifting values to their destination.

4. Example:

7. Google Says: that the time complexity..

9. That’s All..
Thank you