Challenge 3 adventjs midudev - The Naughty Elf

Juneiker Castillo

Problem Statement

In Santa's workshop, a naughty elf has been playing around in the gift manufacturing chain, adding or removing an unplanned step.

You have the original sequence of steps in the manufacturing process original and the modified sequence modified that may include an extra step or miss a step.

Your task is to write a function that identifies and returns the first extra step that has been added or removed in the manufacturing chain. If there is no difference between the sequences, return an empty string.

const original = 'abcd'
const modified = 'abcde'
findNaughtyStep(original, modified) // 'e'

const original = 'stepfor'
const modified = 'stepor'
findNaughtyStep(original, modified) // 'f'

const original = 'abcde'
const modified = 'abcde'
findNaughtyStep(original, modified) // ''

Considerations:

• There will always be one step of difference or none.
• The modification can occur anywhere in the chain.
• The original sequence can be empty.

My Solution

function findNaughtyStep(original, modified) {

  if(original === modified){
     return ''
  }

  let differentElementIndex = 0;

  for(let i = 0; original[i] === modified[i]; i++){
    differentElementIndex = i + 1;
  }

  return original.length > modified.length ? original[differentElementIndex] : modified[differentElementIndex];

}

1. Declare a conditional statement that returns an empty string if the original string is equal to the modified string.
2. Initialize a variable differentElementIndex to 0, which will store the index where the elements at the same position in both strings are different.
3. Create a for loop that increments a variable i while original[i] === modified[i] are equal. When they are not equal, assign the value of the current index + 1 to differentElementIndex.
4. Finally, check if the string named original is longer than the modified string. If true, extract the element at the differentElementIndex obtained previously. Otherwise, if modified is longer, extract the element from the modified string.

Code Challenge 3

Previous Challenges:

1. Challenge 1 advent JS 2023
2. Challenge 2 advent JS 2023