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Update k-th.md #1448

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2 changes: 1 addition & 1 deletion src/sequences/k-th.md
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Expand Up @@ -68,7 +68,7 @@ T order_statistics (std::vector<T> a, unsigned n, unsigned k)

## Notes
* The randomized algorithm above is named [quickselect](https://en.wikipedia.org/wiki/Quickselect). You should do random shuffle on $A$ before calling it or use a random element as a barrier for it to run properly. There are also deterministic algorithms that solve the specified problem in linear time, such as [median of medians](https://en.wikipedia.org/wiki/Median_of_medians).
* A deterministic linear solution is implemented in C++ standard library as [std::nth_element](https://en.cppreference.com/w/cpp/algorithm/nth_element).
* [std::nth_element](https://en.cppreference.com/w/cpp/algorithm/nth_element) solves this in C++ but gcc's implementation runs in worst case $O(n \log n )$ time.
* Finding $K$ smallest elements can be reduced to finding $K$-th element with a linear overhead, as they're exactly the elements that are smaller than $K$-th.

## Practice Problems
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