Swap Nodes in Pairs

Question

Given a linked list, swap every pair of nodes and return its head.

Input: head = [1 -> 2 -> 3 -> 4]

Output: [2 -> 1 -> 4 -> 3]

Input: head = [4 -> 6 -> 8]

Output: [6 -> 4 -> 8]

What are some questions you'd ask an interviewer?

What should the resulting linked list look like after swapping its pairs of nodes? head = [0 -> 5 -> 10 -> 20 -> 35]

[0 -> 10 -> 20 -> 5 -> 35]

[0 -> 10 -> 5 -> 35 -> 20]

[5 -> 0 -> 10 -> 35 -> 20]

[5 -> 0 -> 20 -> 10 -> 35]