Yeah I was a little confused about all the people saying they've already given up on day 1. Seems like everyone's just really overcomplicating this. Why is everyone jumping to "replace the word strings with the digits" instead of just doing exactly what the problem says and... finding the first and last occurrence?

1. Build a list of values with corresponding string matches: [ 0 => ['zero', '0'], 1 => ['one', '1'], ...]

2. Loop through that and find the index of each within the input string, maintaining the lowest seen index + associated value.

3. When done, return value.

To find the last occurrence... just reverse the input string and all the search strings.

I'm not even sure it's all that verbose. If you exclude the part where I hardcoded an array of ten digits, it was... 11 lines of code, a third of which are closing braces. I'm sure I could cut it in half if I used some builtins for mapping/reducing/etc.

Same here. I'm using regex and I was wondering how to make it go backwards. After a moment of thought, that seems silly, so I just reversed the string and the regex and do the scan.