Reverse Linked List
Recognize the pattern
Brute force idea
The naive version of Reverse Linked List sounds like this: Store values in array, build reversed list. That direct path helps you understand the question, but it tends to treat every possibility as brand new instead of learning from earlier steps.
Better approach
The real unlock in Reverse Linked List comes when you notice this: Iterative: three pointers (prev, curr, next), reverse each link. Instead of recomputing the world every time, you preserve just enough context to let the next decision become obvious.
Key invariant
The compass for Reverse Linked List is this: At each step, curr.next points to prev, then all three pointers advance. As long as that statement keeps holding, you can trust the steps built on top of it.
Watch out for
One easy way to drift off course in Reverse Linked List is this: Losing the next node reference — save next before reversing the link. The fix is usually to return to the meaning of each move, not just the steps themselves.