private void printTrieUtil(TrieNode root) {
            if (root == null) {
                return;
            }
            for (int i = 0; i < root.child.length; i++) {
                if (root.child[i] != null) {
                    System.out.println((char)(i + 'a'));
                    printTrieUtil(root.child[i]);
                }
            }
        }
Date 03/04/2016
@author Tushar Roy

Search for dictionary words in the board.
Idea is to use trie for the dictionary which keeps search
very efficient.

https://leetcode.com/problems/word-search-ii/
src/com/interview/graph/Boggle.java