Exclusive Elements - codepath/compsci_guides GitHub Wiki

Unit 3 Session 2 (Click for link to problem statements)

TIP102 Unit 1 Session 2 Standard (Click for link to problem statements)

Problem Highlights

• 💡 Difficulty: Easy
• ⏰ Time to complete: 10 mins
• 🛠️ Topics: List Manipulation, Iteration

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 exclusive_elements() should take two integer lists lst1 and lst2 and return a new list that contains elements that are exclusive to each list (i.e., elements that are in lst1 but not in lst2, and vice versa).

HAPPY CASE
Input: lst1 = ["pooh", "roo", "piglet"], lst2 = ["piglet", "eeyore", "owl"]
Expected Output: ["pooh", "roo", "eeyore", "owl"]

Input: lst1 = ["pooh", "roo"], lst2 = ["piglet", "eeyore", "owl", "kanga"] 
Expected Output: ["pooh", "roo", "piglet", "eeyore", "owl", "kanga"]

EDGE CASE
Input: lst1 = ["pooh", "roo", "piglet"], lst2 = ["pooh", "roo", "piglet"]
Expected Output: []

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Define a function that iterates through both lists to find elements unique to each list, and then combines these elements into a new list.

1. Define the function `exclusive_elements(lst1, lst2)`.
2. Initialize two empty lists: `exclusive_lst1` and `exclusive_lst2`.
3. Use a for loop to iterate through each item in `lst1`.
   a. If the item is not in `lst2`, append it to `exclusive_lst1`.
4. Use a for loop to iterate through each item in `lst2`.
   a. If the item is not in `lst1`, append it to `exclusive_lst2`.
5. Return the concatenation of `exclusive_lst1` and `exclusive_lst2`

⚠️ Common Mistakes

• Not correctly identifying the elements that are exclusive to each list.
• Forgetting to handle cases where the lists may be empty.

I-mplement

Implement the code to solve the algorithm.

def exclusive_elements(lst1, lst2):
    exclusive_lst1 = []
    exclusive_lst2 = []
    
    # Find elements in lst1 that are not in lst2
    for item in lst1:
        if item not in lst2:
            exclusive_lst1.append(item)
    
    # Find elements in lst2 that are not in lst1
    for item in lst2:
        if item not in lst1:
            exclusive_lst2.append(item)
    
    return exclusive_lst1 + exclusive_lst2