Python Program For Recursive Selection Sort For Singly Linked List – Swapping Node Links
Given a singly linked list containing n nodes. The problem is to sort the list using the recursive selection sort technique. The approach should be such that it involves swapping node links instead of swapping node data.
Input: 10 -> 12 -> 8 -> 4 -> 6 Output: 4 -> 6 -> 8 -> 10 -> 12
In Selection Sort, we first find the minimum element, swap it with the beginning node and recur for the remaining list. Below is the recursive implementation of these steps for the linked list.
recurSelectionSort(head) if head->next == NULL return head Initialize min = head Initialize beforeMin = NULL Initialize ptr = head while ptr->next != NULL if min->data > ptr->next->data min = ptr->next beforeMin = ptr ptr = ptr->next if min != head swapNodes(&head, head, min, beforeMin) head->next = recurSelectionSort(head->next) return head swapNodes(head_ref, currX, currY, prevY) head_ref = currY prevY->next = currX Initialize temp = currY->next currY->next = currX->next currX->next = temp
The swapNodes(head_ref, currX, currY, prevY) is based on the approach discussed here but it has been modified accordingly for the implementation of this post.
Linked list before sorting: 10 12 8 4 6 Linked list after sorting: 4 6 8 10 12
Time Complexity: O(n2)
Auxiliary Space: O(n)
Please refer complete article on Recursive selection sort for singly linked list | Swapping node links for more details!