@mel_zoom
You got it right there. I think you should first implement it using the slow (list) method. When that works you can look into some faster ways to manage the words, such as trie, binary tree or hash table.
If you keep your program well structured, and separate the "lookup" and "insert" into separate routines you should have no problems changing the implementation when/if desired.
I do this quite a lot: I get all the simpler parts going first, and those work okay I tackle the bigger problem. It is easy to overwhelm yourself with tons of work, it helps if you keep things organized, and don't try to solve everything at once.
In my solution to stage 3 I have both binary tree and trie routines, toggleable with a #define. I could code the simple binary tree out of memory, and since I had set of simple functions for it, it was trivial to add conditional trie routines later on.
I guess what I am trying to say is: Don't be too hard on yourself and don't demand perfection from the beginning. Allow yourself to use simple(r) solutions, it is enough to recognize that better solutions exist. You can always improve the code after the basics work. (And in case you can't get the advanced solution working, at least you have the simpler one that DOES ;-))
