Odd Even Linked List – Solution & Complexity

The optimal Odd Even Linked List solution runs in O(n) time and O(1) space. Two interleaved pointers splice odd- and even-positioned nodes onto separate chains in one pass, then the even chain is reattached after the odd chain's tail (Rust rebuilds via a Vec of values instead of in-place splicing, to avoid holding two simultaneous mutable borrows into one Option<Box<ListNode>> chain).

Two interleaved pointers splice odd- and even-positioned nodes onto separate chains in one pass, then the even chain is reattached after the odd chain's tail (Rust rebuilds via a Vec of values instead of in-place splicing, to avoid holding two simultaneous mutable borrows into one Option<Box<ListNode>> chain). This gives O(n) time complexity, and is a classic linked list, two pointers, and in place problem.

We provide a worked Odd Even Linked List solution in Python, JavaScript, Java, Go, Rust, C++ & Ruby with a step-by-step explanation above. You can also open the interactive editor to write and run your own Python solution against the test cases in the browser.

Odd Even Linked List is generally rated Medium. It tests linked list, two pointers, and in place, which are common coding-interview patterns.