Solution: Reverse Nodes in k-Group

Explore the in-place linked list manipulation pattern to reverse nodes in groups of k efficiently. Learn to identify k-sized groups, reverse them without extra memory, and reattach segments to maintain list integrity. This lesson helps you implement and understand an optimized O(n) time and O(1) space complexity solution essential for coding interviews.

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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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