I’ll admit it up front, this is not as much of a “when to use it” post as it is a “what is it” post. Never fear, I’ll still fill you all in on when to use it. Also, I’m talking about the data structure for storing strings, not the synonym for attempts.
What is it?
A trie is a data structure that is used for fast string searching. A trie has a root node, and a node for each character in the string. The nodes are constructed such that traversing the tree from the root to a leaf reconstructs one of the strings that is stored in it.