HulkSmash - codepath/compsci_guides GitHub Wiki

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

Problem Highlights

  • 💡 Difficulty: Easy
  • ⏰ Time to complete: 10 mins
  • 🛠️ Topics: Arrays, Conditionals, Iteration

U-nderstand

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

  • Q: What is the input to the function?

    • A: The input is a single integer n.

  • Q: What is the expected output of the function?

    • A: The function should return a list of strings, where each string represents a number or a specific word ("Hulk", "Smash", "HulkSmash") depending on divisibility rules.

  • Q: What are the specific rules for the output?

    • A:
      • If the index i is divisible by 3 and 5, the output should be "HulkSmash".
      • If the index i is divisible by 3, the output should be "Hulk".
      • If the index i is divisible by 5, the output should be "Smash".
      • Otherwise, the output should be the index i itself as a string.

  • Q: What should the function return if n is 1?

    • A: The function should return a list with a single element, "1".

  • Q: Are there any constraints on the input?

    • A: The input n is assumed to be a positive integer.

-The function hulk_smash() should take an integer n and return a 1-indexed string array answer where:

answer[i] == "HulkSmash" if i is divisible by 3 and 5. answer[i] == "Hulk" if i is divisible by 3. answer[i] == "Smash" if i is divisible by 5. answer[i] == i (as a string) if none of the above conditions are true.

HAPPY CASE
Input: 3
Expected Output: ["1", "2", "Hulk"]

Input: 5
Expected Output: ["1", "2", "Hulk", "4", "Smash"]

Input: 15
Expected Output: ["1", "2", "Hulk", "4", "Smash", "Hulk", "7", "8", "Hulk", "Smash", "11", "Hulk", "13", "14", "HulkSmash"]

EDGE CASE
Input: 1
Expected Output: ["1"]

Input: 0
Expected Output: []

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Iterate from 1 to n, applying the given rules to determine the string to append to the result list.

1. Initialize an empty list `answer`.
2. Iterate through the range from 1 to `n` (inclusive).
    a. If the current number is divisible by 3 and 5, append "HulkSmash" to `answer`.
    b. If the current number is divisible by 3, append "Hulk" to `answer`.
    c. If the current number is divisible by 5, append "Smash" to `answer`.
    d. If none of the above conditions are true, append the current number (as a string) to `answer`.
3. Return `answer`.

⚠️ Common Mistakes

  • Forgetting to handle the case where n is 0.
  • Incorrectly checking divisibility conditions.

I-mplement

Implement the code to solve the algorithm.

def hulk_smash(n):
    answer = []
    
    for i in range(1, n + 1):
        if i % 3 == 0 and i % 5 == 0:
            answer.append("HulkSmash")
        elif i % 3 == 0:
            answer.append("Hulk")
        elif i % 5 == 0:
            answer.append("Smash")
        else:
            answer.append(str(i))
    
    return answer