Reorder List — Medium Coding Interview Question

Given the head of a singly linked list, reorder it to be on the form: L0 -> Ln -> L1 -> Ln-1 -> L2 -> Ln-2 -> .... You may not modify node values, only the nodes themselves.

Example

Input: values = [1,2,3,4]

Output: [1,4,2,3]

Constraints

• The number of nodes is in the range [1, 5 × 10⁴]
• 1 ≤ Node.val ≤ 1000

Topics & Companies

Topics: linked-list, two-pointers

Asked by: Amazon, Meta, Microsoft

Optimal Solution Complexity

Time complexity: O(n). Space complexity: O(1).

Practice more

• All DSA Problems
• DSA Patterns