Double Trouble

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

Problem Highlights

• 💡 Difficulty: Easy
• ⏰ Time to complete: 5 mins
• 🛠️ Topics: List Iteration, Loops, Return Statements

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?

• The function doubled() should take a list of integers, hunny_jars, and return a new list where each element is multiplied by 2.

HAPPY CASE
Input: [1, 2, 3]
Expected Output: [2, 4, 6]

Input: [4, 5, 6]
Expected Output: [8, 10, 12]

EDGE CASE
Input: []
Expected Output: []

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.

This problem falls under: List Iteration and Transformation.

3: P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Define a function that iterates through the list, multiplies each element by 2, and stores the results in a new list which is then returned.

1. Define the function `doubled(hunny_jars)`.
2. Initialize an empty list `doubled_jars` to store the doubled values.
3. Iterate through each element in `hunny_jars`.
4. Multiply each element by 2 and append it to `doubled_jars`.
5. Return `doubled_jars`.

⚠️ Common Mistakes

• Forgetting to initialize the result list.
• Not correctly multiplying each element by 2.

4: I-mplement

Implement the code to solve the algorithm.

def doubled(hunny_jars):
    # Create a new list to store the doubled values
    doubled_jars = []
    
    # Loop through each element in the input list
    for jar in hunny_jars:
        # Multiply the element by 2 and add it to the new list
        doubled_jars.append(jar * 2)
    
    # Return the new list
    return doubled_jars

5: R-eview

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

Call the function with the provided examples:

print(doubled([1, 2, 3]))   # Expected Output: [2, 4, 6]
print(doubled([4, 5, 6]))   # Expected Output: [8, 10, 12]
print(doubled([]))          # Expected Output: []
print(doubled([0, 1, -1]))  # Expected Output: [0, 2, -2]

Expected outputs:

[2, 4, 6]
[8, 10, 12]
[]
[0, 2, -2]

6: E-valuate

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

• Time Complexity: O(n) where n is the number of elements in the list since we need to iterate through all elements.
• Space Complexity: O(n) for the new list that stores the doubled values.