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The iterative version came out fine, three pointers, prev/curr/next, pretty mechanical once you've done it a few times.
Start by clarifying the problem and edge cases, then walk through the iterative solution with pointer manipulation, followed by the recursive solution. Emphasize time and space complexity for both approaches and discuss trade-offs.
Pro tip: Mention that the recursive solution uses O(n) stack space, which can cause stack overflow for large lists, while the iterative solution is O(1) space. This shows awareness of practical constraints.
Confirm the problem: reverse a singly linked list and return new head. Discuss edge cases: empty list, single node, two nodes.
Explain using three pointers: prev, curr, next. Iterate through list, reversing pointers, until curr is null. Return prev as new head.
Base case: if head is null or head.next is null, return head. Recursively reverse the rest, then adjust pointers: head.next.next = head; head.next = null. Return new head from recursion.
State time complexity O(n) for both. Space: iterative O(1), recursive O(n) due to call stack.
Discuss when to prefer iterative (memory constraints) vs recursive (simplicity). Mention testing with edge cases and potential follow-ups like reversing in groups.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.