Reverse a singly linked list. Provide iterative O(1)-space and recursive solutions, analyze time/space, and handle edge cases: empty list, one node, very long list (stack depth), and a sublist reversal between positions m and n. Then extend to reverse nodes in k groups with O(1) extra space, preserving leftover tail order. Explain how you would detect and reject cyclic lists before reversing.

This question evaluates understanding of linked list manipulation including pointer operations, in-place reversal techniques, recursion and stack-depth considerations, cycle detection, and time/space complexity analysis.

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Reverse linked lists, including k-group | NVIDIA Interview Question

Singly Linked List Reversal — Variants and Edge Cases

You are given a standard singly linked list with nodes of the form:

Node fields: value, next
Head pointer may be null (empty list).
Assume 1-indexed positions for m and n.

Implement and analyze the following:

A) Reverse Entire List

Provide an iterative in-place solution that uses O(1) extra space.
Provide a recursive solution.
Analyze time and space complexity of both.
Explicitly handle edge cases: empty list, single-node list, and very long lists (stack depth considerations for recursion).

B) Reverse a Sublist [m, n]

Reverse the nodes from position m to n (inclusive), in-place, and return the head. Assume 1 ≤ m ≤ n ≤ length of list.

C) Reverse Nodes in k-Groups

Reverse the list in contiguous groups of size k using O(1) extra space. If the final group has fewer than k nodes, leave that tail group as-is.

D) Cycle Detection Before Reversal

Explain and implement how to detect a cycle in the list and reject (do not attempt to reverse) if a cycle is present.

You may use pseudo-code or code in a language of your choice.

Singly Linked List Reversal — Variants and Edge Cases

You are given a standard singly linked list with nodes of the form:

Node fields: value, next
Head pointer may be null (empty list).
Assume 1-indexed positions for m and n.

Implement and analyze the following:

A) Reverse Entire List

Provide an iterative in-place solution that uses O(1) extra space.
Provide a recursive solution.
Analyze time and space complexity of both.
Explicitly handle edge cases: empty list, single-node list, and very long lists (stack depth considerations for recursion).

B) Reverse a Sublist [m, n]

Reverse the nodes from position m to n (inclusive), in-place, and return the head. Assume 1 ≤ m ≤ n ≤ length of list.

C) Reverse Nodes in k-Groups

Reverse the list in contiguous groups of size k using O(1) extra space. If the final group has fewer than k nodes, leave that tail group as-is.

D) Cycle Detection Before Reversal

Explain and implement how to detect a cycle in the list and reject (do not attempt to reverse) if a cycle is present.

You may use pseudo-code or code in a language of your choice.

Reverse linked lists, including k-group

Quick Overview

Singly Linked List Reversal — Variants and Edge Cases

A) Reverse Entire List

B) Reverse a Sublist [m, n]

C) Reverse Nodes in k-Groups

D) Cycle Detection Before Reversal

Solution

Comments (0)

Reverse linked lists, including k-group

Quick Overview

Singly Linked List Reversal — Variants and Edge Cases

A) Reverse Entire List

B) Reverse a Sublist [m, n]

C) Reverse Nodes in k-Groups

D) Cycle Detection Before Reversal

Solution

Comments (0)