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Radix Tree for Order ID Mapping

Hard · data_structures · Quant Developer interview question · data_structures, trie, pointers, optimization

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