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copied!<p>You might want to use a <a href="http://en.wikipedia.org/wiki/Trie" rel="nofollow noreferrer">Trie</a> or other tree-based data structure for storing your string data. </p> <blockquote> <p>A trie can also be used to replace a hash table, over which it has the following advantages:</p> <ul> <li><p>Looking up data in a trie is faster in the worst case, O(m) time, compared to an imperfect hash table. An imperfect hash table can have key collisions. A key collision is the hash function mapping of different keys to the same position in a hash table. The worst-case lookup speed in an imperfect hash table is O(N) time, but far more typically is O(1), with O(m) time spent evaluating the hash.</p></li> <li><p>There are no collisions of different keys in a trie.</p></li> <li>Buckets in a trie which are analogous to hash table buckets that store key collisions are only necessary if a single key is associated with more than one value.</li> <li>There is no need to provide a hash function or to change hash functions as more keys are added to a trie.</li> <li>A trie can provide an alphabetical ordering of the entries by key.</li> </ul> <p>Tries do have some drawbacks as well:</p> <ul> <li>Tries can be slower in some cases than hash tables for looking up data, especially if the data is directly accessed on a hard disk drive or some other secondary storage device where the random access time is high compared to main memory.</li> <li>It is not easy to represent all keys as strings, such as floating point numbers, which can have multiple string representations for the same floating point number, e.g. 1, 1.0, 1.00, +1.0, etc.</li> <li>Tries are frequently less space-efficient than hash tables.</li> </ul> </blockquote> <p>(see <a href="http://en.wikipedia.org/wiki/Trie" rel="nofollow noreferrer">http://en.wikipedia.org/wiki/Trie</a>)</p>

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