Middle of Linked List

Problem

Return the value of the middle node. For even lengths, return the second middle node.

Examples

Example 1

Input: [1,2,3,4,5,6]

Output: 4

Example 2

Input: [7,8,9]

Output: 8

Input and output use JSON-compatible values. For linked-list and tree questions, arrays represent the node structure as described above. Your code should implement solve(input).

Write your solutionImplement solve(input). Your draft is saved in this browser.

Compiler

How to solve Middle of Linked List

Return the value of the middle node. For even lengths, return the second middle node. Move a fast pointer twice as quickly as a slow one. The reference implementation illustrates this approach; check the example and edge cases.

Time and space complexity

O(n) time and O(1) additional space for a linked list.

Practise and improve

Choose JavaScript, TypeScript or Python, complete the starter code, then select Run Tests. Request a hint when you need guidance, or choose View solution and confirm if you would like to study the reference implementation.