Reverse a Singly Linked List

Problem: reverse a singly linked list.

Thinking: there may be several cases.

1. Acyclic list
2. Completely cyclic list (all nodes are in the cycle/loop)
3. Partially cyclic list (at least one node not in the cycle/loop)

This post discusses Case 1.

Requirement for Case 1: O(n) in time and O(1) in space.
Idea: use 2 pointers for exchange and a 3rd one to temporarily record the next node.
Code:


Related Posts:

Discussion about Case 2

Discussion about Case 3