Solution: Reverse Nodes in k-Group

Explore methods to reverse nodes in a linked list in groups of a given size k without altering node values. Learn an optimized in-place approach that reduces space complexity to O(1) while maintaining O(n) time complexity. Understand step-by-step how to identify groups, reverse nodes in place, and reattach them, enabling efficient linked list reordering under memory constraints.

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Statement
Solution
- Naive approach
- Optimized approach using in-place manipulation of a linked list

Statement

The task is to reverse the nodes in groups of $k$ in a given linked list, where $k$ is a positive integer, and at most the length of the linked list. If any remaining nodes are not part of a group of $k$ , they should remain in their original order.

It is not allowed to change the values of the nodes in the linked list. Only the order of the nodes can be modified.

Note: Use only $O(1)$ extra memory space.

Constraints:

Let n be the number of nodes in a linked list.

$1 \leq$ k $\leq$ n $\leq 500$

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