ternary-search-tree

I had been using Ternary Search Tree for a while, as the data structure to implement a auto complete drop down combo box. Which means, when user type "fo", the drop down combo box will display foo food football The problem is, my current used of Ternary Search Tree is case sensitive. My implementation is as follow. It had been used by real world for around 1++ yeas. Hence, I consider it as quite reliable. My Ternary Search Tree code However, I am looking for a case insensitive Ternary Search Tree, which means, when I type "fo", the drop down combo box will show me foO Food fooTBall Here are

I need to know if a ternary tree is better than a hash table . I came across this question in a reply to another question I had where someone said that ternary trees are often faster than hash tables. I found that hard to believe, so I decided to research a little into it. This one website from Princeton appears to be the source of the belief. I took a look at algorithm which is described to be O(log n + k) where n is the number of words stored, and k is the length of the key. It seems to me that the only way this could be faster is if you are often searching for elements that are not already