Наибольшее составное слово в массиве. (состоит только из слов, заданных в данном массиве)

LongestWord.java

import java.util.ArrayList;
import java.util.Comparator;
import java.util.TreeMap;

public class LongestWord {

	public static void main(String[] args) {
		/* Creation an array of words */
		String words[] = { "five", "fivetwo", "fourfive", "fourfivetwo", "one", "onefiveone", "two", "twofivefourone" };
		/* Output */
		System.out.println("Longest Compound word : " + longestCompundWord(words));

	}

	/* Method that begins the search the longest a compound word */
	private static String longestCompundWord(String[] words) {
		/*
		 * The creation of the storage of all the words and the TreeMap to sort
		 * the words in ascending order by using a comparator
		 */
		ArrayList<String> dictionary = new ArrayList<String>();
		TreeMap<String, Integer> wordTree = new TreeMap<String, Integer>(new Comparator<String>() {

			@Override
			public int compare(String o1, String o2) {
				return o1.length() - o2.length();
			}
		});
		/* Put the words from array to the storage and TreeMap */
		for (int i = 0; i < words.length; i++) {
			wordTree.put(words[i], i);
			dictionary.add(words[i]);
		}
		/* Call next method */
		return findLongestCompoundWord(wordTree, dictionary);

	}

	/*
	 * Check that the word is really a compound. We look at the contents of the
	 * word in storage, cut off a letter to the front and back and check the
	 * presence of parts word in the storage
	 */
	private static boolean isCompoundWord(String word, ArrayList<String> dictionary) {
		if (dictionary.contains(word))
			return true;
		for (int i = 1; i < word.length(); i++) {
			String prefix = word.substring(0, i);
			if (isCompoundWord(prefix, dictionary)) {
				String remainder = word.substring(i, word.length());
				if (remainder.length() == 0)
					return true;
				return isCompoundWord(remainder, dictionary);
			}
		}
		return false;
	}

	/*
	 * Take the longest word from TreeMap and check whether it is a compound.
	 * Remove this word from the storage and TreeMap
	 */
	public static String findLongestCompoundWord(TreeMap<String, Integer> wordTree, ArrayList<String> dictionary) {
		while (wordTree.size() > 0) {
			String word = wordTree.lastKey();
			wordTree.remove(word);
			dictionary.remove(word);
			if (isCompoundWord(word, dictionary))
				return word;
		}
		return "";
	}

}