Reorder List

Given a singly linked list

    L: L0 → L1 → … → Ln-1 → Ln,

reorder it to:

    L0 → Ln → L1 → Ln-1 → L2 → Ln-2 → …

You must do this in-place without altering the nodes’ values.

For example,
Given {1,2,3,4}, reorder it to {1,4,2,3}.

NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.