System-Scale & Probabilistic Structures

We are building a DDoS mitigation filter monitoring billions of network packets per minute. We need to count the frequency of each source IP address in real-time to detect anomalous spikes. Using a standard hash map of counters would require tens ...Read more

We need dynamic prefix sums and range sum queries over a stream of financial ledger transactions where numbers are constantly updated. A standard array has O(1) update but O(N) range sum. A prefix sum array has O(1) range sum but O(N) ...Read more