You are given a dictionary, such as /usr/share/dict/words, containing a list of words, one per line. You are also given seven tiles. Each tile is either blank or contains a single lowercase letter (a-z).
List all of the words from the dictionary that can be produced by using some or all of the seven tiles, in any order. A blank tile is a wildcard, and can be used in place of any letter.
Try to use a minimal amount of memory.
1. Find all of the words that can be formed if you don't have to deal with blank tiles. (You may skip this step and go straight to step 2).
2. Find all of the words that can be formed, including those where blank tiles are used as wildcards.
3. Would you do things differently if you had to process several hundred tile sets with the same dictionary?