# `COUNT_DISTINCT`

[Count-distinct problem](https://en.wikipedia.org/wiki/Count-distinct_problem).

## References

### Wikipedia

#### Probabilistic Counting with Stochastic Averaging (PCSA)

* [Sketch of the Day: Probabilistic Counting with Stochastic Averaging (PCSA)](https://agkn.wordpress.com/2013/04/02/sketch-of-the-day-probabilistic-counting-with-stochastic-averaging-pcsa/)
* [Sketch of the Day: Probabilistic Counting with Stochastic Averaging (PCSA)](https://research.neustar.biz/2013/04/02/sketch-of-the-day-probabilistic-counting-with-stochastic-averaging-pcsa/)
* [Flajolet–Martin algorithm](https://en.wikipedia.org/wiki/Flajolet%E2%80%93Martin_algorithm)
* [Probabilistic Counting Algorithms for Data Base Applications](http://algo.inria.fr/flajolet/Publications/src/FlMa85.pdf)

<!-- * [Probabilistic Counting with Stochastic Averaging](https://bana.io/blog/pcsa/) -->

### Papers

TODO.

### Misc

TODO.

### Books

* [Chapter 4 of Mining Data Streams of Mining of Massive Datasets by Jure Leskovec, Anand Rajaraman, Jeff Ullman](http://infolab.stanford.edu/~ullman/mmds/ch4.pdf).
* [Mining of Massive Datasets by Jure Leskovec, Anand Rajaraman, Jeff Ullman](http://www.mmds.org/).

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