Echo JS 0.11.0

#2, might as well use an object... the "encode" is meaningless since it won't be a numeric comparison.  may as well use `this["_" + word] = true;` prepending the underscore only to avoid use of reserved words, or overriding object prototypes.

#5 the linked list's "insert" doesn't account for middle-insert or changing current position.

The solution to question 4 part 2 is also a bit odd. Left a comment about that here: https://medium.com/@simon.kusterer/the-suggested-second-solution-of-question-4is-quite-odd-imo-3891ff46bfd6

We have interviewed some people and we think *they* are doing it wrong. Let’s try explaining to them that we are going to ask them to guess that arrays-only solution is actually “guess that you need to implement your own hashmap”. And ask a lot of computer science stuff because we heard that google uses it.

Apart from that a decent article for some aspects of interview preparations.