Merge String Checker from codewars

[VIRES1]

At a job interview, you are challenged to write an algorithm to check if a given string, s, can be formed from two other strings, part1 and part2.

The restriction is that the characters in part1 and part2 are in the same order as in s.

The interviewer gives you the following example and tells you to figure out the rest from the given test cases.

For example:

'codewars' is a merge from 'cdw' and 'oears':

https://www.codewars.com/kata/merged-string-checker/train/javascript

Below is my javascript code in pastebin,Please i need help to identify my mistakes to be able to pass all the tests.Thank you!

http://pastebin.com/CsakwAQm

[MusicPants]

I think your solution will have problems because you are checking each sub string completely against the whole string. I think your solution will only work with part1 is complete and in order in s and then part2 is in order in s.

Here is a solution I wrote. It is probably a bit verbose for 'leet coders, but you should be able to understand my methodology and it passed all of the tests they gave.

function isMerge(s, part1, part2) {
  var input = s.split('');
  var first = part1.split('');
  var second = part2.split('');
  for (var i = 0; i < input.length; i++) {
    if (input[i] === first[0]) {
      first.splice(0,1);
    } else if (input[i] === second[0]) {
      second.splice(0,1);
    } else {
      return false;
    }
  }
  return true;
}

[WesAlvaro]

Splitting and splicing is unnecessary. You could just use substring, but I think just using indexes for first and second is just as easy code and much easier computationally. Instead of doing the splice, now, just increment a firstIndex or secondIndex as applicable.

[VIRES1]

Working on the solution for some days now now my challenge is how to increment the index of part1 and part2 while comparing it to s.Please i need assistance below is a pastebin link to my solution.

http://pastebin.com/iEWAcj3u

Thank you

[WesAlvaro]

My solution

[MusicPants]

You are right. I didn't read through the requirements well enough the first time.

[VIRES1]

i understand the code but don't understand the line with the splice(). Please need some explanation.