Java Program for ShellSort (original) (raw)

Last Updated : 10 Jun, 2022

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.

Java `

// Java implementation of ShellSort class ShellSort { /* An utility function to print array of size n*/ static void printArray(int arr[]) { int n = arr.length; for (int i = 0; i < n; ++i) System.out.print(arr[i] + " "); System.out.println(); }

/* function to sort arr using shellSort */ int sort(int arr[]) { int n = arr.length;

// Start with a big gap, then reduce the gap for (int gap = n / 2; gap > 0; gap /= 2) { // Do a gapped insertion sort for this gap size. // The first gap elements a[0..gap-1] are already // in gapped order keep adding one more element // until the entire array is gap sorted for (int i = gap; i < n; i += 1) { // add a[i] to the elements that have been gap // sorted save a[i] in temp and make a hole at // position i int temp = arr[i];

// shift earlier gap-sorted elements up until 
// the correct location for a[i] is found 
int j; 
for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) 
 arr[j] = arr[j - gap]; 

// put temp (the original a[i]) in its correct 
// location 
arr[j] = temp; 

} } return 0; }

// Driver method public static void main(String args[]) { int arr[] = { 12, 34, 54, 2, 3 }; System.out.println("Array before sorting"); printArray(arr);

ShellSort ob = new ShellSort(); ob.sort(arr);

System.out.println("Array after sorting"); printArray(arr); } } /*This code is contributed by Rajat Mishra */

`

Output:

Array before sorting 12 34 54 2 3 Array after sorting 2 3 12 34 54

Time Complexity: O(n2)
Auxiliary Space: O(1)

Please refer complete article on ShellSort for more details!