ShellSort is mainly a variation of Insertion Sort. In insertion sort, we move elements only one position ahead. When an element has to be moved far ahead, many movements are involved. The idea of shellSort is to allow exchange of far items. In shellSort, we make the array h-sorted for a large value of h. We keep reducing the value of h until it becomes 1. An array is said to be h-sorted if all sublists of every h’th element is sorted.
Following is the implementation of ShellSort.
Array before sorting: 12 34 54 2 3 Array after sorting: 2 3 12 34 54
Time Complexity: Time complexity of above implementation of shellsort is O(n2). In the above implementation gap is reduce by half in every iteration. There are many other ways to reduce gap which lead to better time complexity. See this for more details.
Other Sorting Algorithms on GeeksforGeeks/GeeksQuiz:
- Selection Sort
- Bubble Sort
- Insertion Sort
- Merge Sort
- Heap Sort
- Radix Sort
- Counting Sort
- Bucket Sort
- C++ Program for ShellSort
- Java Program for ShellSort
- Merge two sorted arrays in O(1) extra space using Heap
- Merge two sorted arrays in O(1) extra space using QuickSort partition
- Maximum even sum subsequence of length K
- Count all disjoint pairs having absolute difference at least K from a given array
- Maximize sum of given array by rearranging array such that the difference between adjacent elements is atmost 1
- Find a triplet in an array such that arr[i] arr[k] and i < j < k
- Print X array elements closest to the Kth smallest element in the array
- Count array elements with rank not exceeding K
- Calculate server loads using Round Robin Scheduling
- Remove Sub-Directories from a File System
- Difference between Searching and Sorting Algorithms
- Maximize count of pairs (i, j) from two arrays having element from first array not exceeding that from second array
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.