Radix Tree for Order ID Mapping - Quant Developer Interview Question

Problem Description

Mapping 64-bit Order IDs to internal metadata requires deterministic latency to avoid the unpredictable resizing costs and collision risks associated with standard hash maps. A Radix Tree (specifically a 256-ary Trie) offers $O(K)$ performance based on key length rather than the number of elements, providing cache-friendly and collision-free lookups essential for low-latency execution. This data structure processes keys in fixed-size chunks, making it highly efficient for managing dense or spars