Quick Select is a selection algorithm that uses a partitioning strategy similar to quicksort to find the k-th smallest element in an unsorted list. It works by selecting a pivot element and partitioning the list around it, such that all elements smaller than the pivot come before all elements larger than the pivot. It then recursively applies this process to the appropriate subset until the k-th element is identified. For example, to find the median of a list of nine numbers, Quick Select would recursively partition the list until isolating the 5th smallest element.

1. Quick Select (Lomuto Partition)
(Illustration)
Decrease and Conquer Technique

2. Quick Select (Lomuto Partition)
 A selection algorithm to find the k-th smallest
element in an unordered list
Related to the quick sort sorting algorithm
Related to the quick sort sorting algorithm

3. Example
Apply the partition-based algorithm to find the
median of the following list of nine numbers: 4, 1,
10, 8, 7, 12, 9, 2, 15.
10, 8, 7, 12, 9, 2, 15.
k = 9 / 2 = 5
Task: to find the 5th smallest element in the array

10. s = 2
k - 1 = 4
if s > l + k - 1
Proceed with
the right part
of the array