Count-min sketch comes to mind [1]. It's a probabilistic data structure similar to the bloom filter. Learnt about it in this system design video "Top K Problem"

Count-min sketch comes to mind [1]. It's a probabilistic data structure similar to the bloom filter. Learnt about it in this system design video "Top K Problem" [2]. [1] https://en.wikipedia.org/wiki/Count–min_sketch https://en.wikipedia.org/wiki/Count–min_sketch [2] https://www.youtube.com/watch?v=kx-XDoPjoHw https://www.youtube.com/watch?v=kx-XDoPjoHw