HyperLogLog Hit Counter - Computerphile

HyperLogLog is a probabilistic algorithm for estimating the number of unique elements in large datasets using minimal memory. Instead of storing all unique values (which requires massive memory for billions of items), it uses hash functions to track the minimum hash values and estimate cardinality. The algorithm works by hashing input values and counting leading zeros in the binary representation, then using multiple hash functions to reduce estimation noise. This technique is widely used in databases and web servers for efficiently counting unique visitors or elements.