Recall & Review
beginner
What is a circular linked list?
A circular linked list is a linked list where the last node points back to the first node, forming a circle. There is no null at the end.
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intermediate
Why do we need to update the last node when inserting at the beginning of a circular linked list?
Because the last node points to the first node, when we insert a new node at the beginning, the last node's next pointer must be updated to point to the new first node.
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beginner
What happens if the circular linked list is empty and we insert a node at the beginning?
The new node points to itself, making it both the first and last node, forming a single-node circular linked list.
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intermediate
In the insertion at beginning operation, which pointers are changed?
The new node's next pointer is set to the old head. The last node's next pointer is updated to the new node. The head pointer is updated to the new node.
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intermediate
What is the time complexity of inserting a node at the beginning of a circular linked list if we keep a pointer to the last node?
O(1) because we can directly access the last node to update its next pointer without traversing the list.
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In a circular linked list, what does the last node point to?
✗ Incorrect
In a circular linked list, the last node points back to the first node to form a circle.
When inserting at the beginning of a circular linked list, which pointer must be updated besides the new node's next?
✗ Incorrect
The last node's next pointer must point to the new first node to maintain the circular structure.
If the circular linked list is empty, what should the new node's next pointer point to after insertion at beginning?
✗ Incorrect
The new node points to itself to form a single-node circular linked list.
What is the time complexity of inserting at the beginning if you only have a pointer to the head (not the last node)?
✗ Incorrect
Without a pointer to the last node, you must traverse the list to find it, which takes O(n) time.
Which of these is NOT true about circular linked lists?
✗ Incorrect
In circular linked lists, the last node's next is not null; it points to the first node.
Explain step-by-step how to insert a new node at the beginning of a circular linked list.
Think about how the circle is maintained after insertion.
You got /5 concepts.
Why is it important to update the last node's next pointer when inserting at the beginning of a circular linked list?
Consider what happens if the last node still points to the old first node.
You got /4 concepts.