Create the interface of a simple trie implementation.
Trie.Update alwasy updates the value of a node specified with key.
Trie.Update alwasy updates the value of a node specified with key.
Add test cases for Trie.Update() and Trie.Get().
Add test cases for Trie.Update() and Trie.Get().
Add test cases for Trie.Update() and Trie.Get().
Add test cases for Trie.Update() and Trie.Get().
Extract a struct to represent test data.
Use zero for not existing key.
Check the value if the key exists.
Implement a simple trie.
TODO: Replace the current implementation of trie with more efficient one.
Merge branch 'feature/simple-trie'