Leaderboard
Showing:
Pairwise swap elements of a linked list
Easy Accuracy: 43.06% Submissions: 57826 Points: 2

Given a singly linked list of size N. The task is to swap elements in the linked list pairwise.
For example, if the input list is 1 2 3 4, the resulting list after swaps will be 2 1 4 3.
Note: You need to swap the nodes, not only the data. If only data is swapped then driver will print -1.

Example 1:

Input:
LinkedList: 1->2->2->4->5->6->7->8
Output: 2 1 4 2 6 5 8 7
Explanation: After swapping each pair
considering (1,2), (2, 4), (5, 6).. so
on as pairs, we get 2, 1, 4, 2, 6, 5,
8, 7 as a new linked list.

 

Example 1:

Input:
LinkedList: 1->3->4->7->9->10->1
Output: 3 1 7 4 10 9 1
Explanation: After swapping each pair
considering (1,3), (4, 7), (9, 10).. so
on as pairs, we get 3, 1, 7, 4, 10, 9,
1 as a new linked list.

Your Task:
The task is to complete the function pairWiseSwap() which takes the head node as the only argument and returns the head of modified linked list.

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(1).

Constraints:
1 ≤ N ≤ 103

to report an issue on this page.

Editorial

We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?

Yes

All Submissions

My Submissions:

Login to access your submissions.

Pairwise swap elements of a linked list

Output Window