Question

I am trying to create this app on the iphone that given 6 letters, it would output all the possible 3-6 letter english words. I already have a dictionary, I just want to know how to do it.

I searched around and only found those scrabble solvers in python or those word search grid solutions.

I think a brute force search would do, but I’m concerned about the performance. Code is not necessary, a link to an algorithm or the algorithm itself would be fine, I think I’ll be able to manage once I get that.

Thanks!

Answer 1

If you’re concerned about performance, this method might do the trick. It involves some preprocessing but would allow for nearly-instantaneous lookup for anagrams.

1. Create a data structure that maps a String key to a List of Strings (I’m more familiar with Java, so in that case it would be a Map<String,List<String>>) This will store your dictionary.

2. Define a function that takes a string and outputs the same letters arranged alphabetically. For example, hello would become ehllo; kitchen would become cehiknt. I’ll refer to this function as keyify(word)

3. Here’s the preprocessing part: for each item in your dictionary, find the list for that item’s key (keyify(item)) and add that item to the list.

4. When it comes time to look up anagrams of a given word, just look up the list at they keyify of that word. For example, if the input was kitchen, the keyify would be cehiknt, and looking that up in your map should result in a list containing kitchen, chicken and whatever other anagrams of kitchen that I forgot 😛