Add Furniture - codepath/compsci_guides GitHub Wiki

TIP102 Unit 5 Session 1 Standard (Click for link to problem statements)

TIP102 Unit 5 Session 1 Advanced (Click for link to problem statements)

Problem Highlights

• 💡 Difficulty: Easy
• ⏰ Time to complete: 10-15 mins
• 🛠️ Topics: Classes, Object-Oriented Programming, Methods, Data Validation

1: U-nderstand

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

• Established a set (2-3) of test cases to verify their own solution later.
• Established a set (1-2) of edge cases to verify their solution handles complexities.
• Have fully understood the problem and have no clarifying questions.
• Have you verified any Time/Space Constraints for this problem?

• What should the add_item method do?

  • Validate the input item_name and add it to the furniture attribute if valid.

• What constitutes a valid item name?

  • It must be one of the following: "acoustic guitar", "ironwood kitchenette", "rattan armchair", "kotatsu", "cacao tree".

HAPPY CASE
Input: 
alice = Villager("Alice", "Koala", "Normal", "guvnor")
alice.add_item("acoustic guitar")
print(alice.furniture)

Output: 
["acoustic guitar"]

Explanation: 
The `item_name` is valid, so it is added to the `furniture` attribute of `alice`.

EDGE CASE
Input: 
alice = Villager("Alice", "Koala", "Normal", "guvnor")
alice.add_item("nintendo switch")
print(alice.furniture)

Output: 
[]
Invalid item

Explanation: 
The `item_name` is invalid, so it is not added to the `furniture` attribute of `alice`, and an error message is printed.

2: M-atch

Match what this problem looks like to known categories of problems, e.g. Linked List or Dynamic Programming, and strategies or patterns in those categories.

For Object-Oriented Programming problems, we want to consider the following approaches:

• Implement methods to encapsulate behavior.
• Ensure methods perform validation before updating attributes.

3: P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Implement the add_item method to validate and add items to the furniture attribute.

1) Define the `add_item` method in the `Villager` class.
2) Implement validation to check if `item_name` is in the list of valid items.
3) If valid, add `item_name` to the `furniture` attribute.
4) If invalid, print "Invalid item".

⚠️ Common Mistakes

• Forgetting to validate the item_name before adding it to the list.
• Not correctly referencing or updating the furniture attribute.

4: I-mplement

Implement the code to solve the algorithm.

class Villager:
    def __init__(self, name, species, personality, catchphrase):
        self.name = name
        self.species = species
        self.personality = personality
        self.catchphrase = catchphrase
        self.furniture = []

    def add_item(self, item_name):
        valid_items = ["acoustic guitar", "ironwood kitchenette", "rattan armchair", "kotatsu", "cacao tree"]
        if item_name in valid_items:
            self.furniture.append(item_name)
        else:
            print("Invalid item")

5: R-eview

Review the code by running specific example(s) and recording values (watchlist) of your code's variables along the way.

• Instantiate the Villager object alice.
• Validate different item names and check the furniture attribute.
• Ensure invalid item names do not affect the furniture attribute and print an error message.

6: E-valuate

Evaluate the performance of your algorithm and state any strong/weak or future potential work.

Assume N represents the number of valid items.

• Time Complexity: O(1) because checking membership in a small list and appending to a list are constant-time operations.
• Space Complexity: O(1) for each Villager instance because it uses a fixed amount of memory for its attributes and methods.