Recall & Review
beginner
What does the 'push' operation do in a linked list?
It adds a new node at the beginning (head) of the linked list, making it the new first element.
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beginner
In C, what is the typical structure used to represent a node in a singly linked list?
A struct with at least two members: one for data (e.g., int data) and one pointer to the next node (e.g., struct Node* next).
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intermediate
Why do we pass the head pointer by reference (pointer to pointer) when pushing a new node in C?
Because the head pointer itself may change to point to the new node, so we need to modify the original pointer outside the function.
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beginner
What is the time complexity of the push operation in a singly linked list?
O(1) — It takes constant time because we only change a few pointers without traversing the list.
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beginner
Show the basic steps to push a new node with value 'x' onto a linked list in C.
1. Create a new node using malloc.
2. Set new node's data to x.
3. Set new node's next to current head.
4. Update head to new node.
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What pointer type should be passed to a push function to update the head of a linked list in C?
✗ Incorrect
To update the head pointer itself, the function needs a pointer to the head pointer, which is Node**.
What happens to the old head node when a new node is pushed onto the linked list?
✗ Incorrect
The old head node is linked after the new node, becoming the second node.
Which of these is NOT a step in pushing a node onto a linked list?
✗ Incorrect
The new node's next should point to the old head, not always NULL.
What is the output linked list after pushing nodes with values 3, then 5, then 7 onto an empty list?
✗ Incorrect
Each new node is added at the front, so the last pushed (7) is the head.
What is the time complexity of pushing a node onto a singly linked list?
✗ Incorrect
Push operation takes constant time because it only changes pointers at the head.
Explain how the push operation works in a singly linked list using a linked list node in C.
Think about how the new node becomes the first element.
You got /4 concepts.
Describe why the head pointer must be passed as a pointer to pointer when implementing push in C.
Consider how C passes arguments by value.
You got /3 concepts.