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
- C program for Time Complexity plot of Bubble, Insertion and Selection Sort using Gnuplot
- Sorting Algorithm Visualization : Merge Sort
- Median of sliding window in an array
- Find the distance between two person after reconstruction of queue
- Find the minimum cost to cross the River
- Minimize the sum of differences of consecutive elements after removing exactly K elements
- Check if N rectangles of equal area can be formed from (4 * N) integers
- Minimum elements to be removed from the ends to make the array sorted
- Value to be subtracted from array elements to make sum of all elements equals K
- How to sort an array in a single loop?
- Check if a symmetric plus is possible from the elements of the given array
- Sort an Increasing-Decreasing Array
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