Hey, just a heads up. This is not a patricia trie but just a regular trie you showed. The difference is that the patricia trie is a compressed radix tree with radix 2. A radix tree compresses the data so not every letter is a node but nodes without branches are compressed as single nodes. Inserting Cat would be a single node inserting Catalog would only be 2 nodes. Radix 2 means that every node can have 2 edges. This is mostly implemented by storing data in the binary format since comparing bit by bit only every leaves us with 2 possible outcomes.