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Iteratively reverse pointers: track prev, current, and next nodes.
Example:
Input:
head=[1,2,3,4,5]Output:
[5,4,3,2,1]Common Mistakes:
- Losing reference to next node before reversing pointer
- Not returning prev at the end (returning curr which is null)
- Trying to reverse without tracking 3 pointers
- Overcomplicating with recursion when iterative is simpler
Notes:
Fundamental linked list operation. Time O(n), Space O(1) iterative. Can also solve recursively with O(n) space.
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Iteratively reverse pointers: track prev, current, and next nodes.
Example:
Input:
head=[1,2,3,4,5]Output:
[5,4,3,2,1]Common Mistakes:
- Losing reference to next node before reversing pointer
- Not returning prev at the end (returning curr which is null)
- Trying to reverse without tracking 3 pointers
- Overcomplicating with recursion when iterative is simpler
Notes:
Fundamental linked list operation. Time O(n), Space O(1) iterative. Can also solve recursively with O(n) space.
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Reverse Linked List