Medium
Quiz
#143 Reorder List
APPROACH
You are given the head of a singly linked-list arranged as:
L0 → L1 → … → Ln - 1 → Ln
Rearrange the nodes into the following alternating pattern:
L0 → Ln → L1 → Ln - 1 → L2 → Ln - 2 → …
Node values must not be changed; only the node connections may be modified.
Example 1:
L0 → L1 → … → Ln - 1 → Ln
Example 2:
L0 → Ln → L1 → Ln - 1 → L2 → Ln - 2 → …
Example 3:
Input: head = [1,2,3,4]
Output: [1,4,2,3]
Example 4:
Input: head = [1,2,3,4,5]
Output: [1,5,2,4,3]
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What is the optimal approach for this problem?