Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Why In-Place Reversal:** O(n) time, O(1) space. Recursive version uses O(n) stack—fails for long lists (stack overflow). **Algorithm:** Iterate, reverse next pointers: save next, point current to prev, advance prev and curr. Handles empty and single-node. **Analogy in Data...
Why In-Place Reversal: O(n) time, O(1) space. Recursive version uses O(n) stack—fails for long lists (stack overflow).
Algorithm: Iterate, reverse next pointers: save next, point current to prev, advance prev and curr. Handles empty and single-node.
Analogy in Data Eng: Reverse order of events (LIFO processing), undo stacks. Conceptually similar to reversing a stream buffer—process from tail.
def reverse_list(head):
prev = None
while head:
nxt = head.next
head.next = prev
prev, head = head, nxt
return prev
Red Flag: Recursive solution for 1M nodes. Pro-Move: 'We use similar pointer manipulation for our circular buffer—reverse last N items for replay.'
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