Chase List

Unit 5 Session 1 (Click for link to problem statements)

U-nderstand

Understand what the interviewer is asking for by using test cases and questions about the problem.

• How do we insert a node at the beginning of an existing linked list?
  • Create a new node and update its next attribute to point to the previous first node of the list.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Insert a new node dog at the start of the existing linked list by making it point to the cat node, thus updating the start of the list to dog.

1) Create a node `dog` with the value "Spike".
2) Set the `next` attribute of `dog` to `cat`, making `dog` the new first node in the list.
3) The list structure now becomes `dog -> cat -> mouse`.

⚠️ Common Mistakes

• Incorrectly linking the new node, which could disrupt the current list structure.
• Misordering the operations, leading to lost references and broken links.

I-mplement

# Existing code
cat = Node("Tom")
mouse = Node("Jerry")
cat.next = mouse

# New code
dog = Node("Spike")
dog.next = cat