Reverse Linked List II – Solution & Complexity

The optimal Reverse Linked List II solution runs in O(n) time and O(1) space. Dummy-node walk to the node before left, then repeatedly splices the next node to the front of the reversed segment (Rust rebuilds via a Vec instead — O(n) auxiliary — to avoid move/borrow conflicts on Option<Box<ListNode>>).

Dummy-node walk to the node before left, then repeatedly splices the next node to the front of the reversed segment (Rust rebuilds via a Vec instead — O(n) auxiliary — to avoid move/borrow conflicts on Option<Box<ListNode>>). This gives O(n) time complexity, and is a classic linked list and pointers problem.

We provide a worked Reverse Linked List II 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.

Reverse Linked List II is generally rated Medium. It tests linked list and pointers, which are common coding-interview patterns.