select and partition

(classic problem)

Definition: Given an array A of n elements and a positive integer k ≤ n, find the kth smallest element of A and partition the array such that A[1], …, A[k-1] ≤ A[k] ≤ A[k+1], …, A[n].

See also select kth element, Select, MODIFIND, Find.

Note: Algorithms to solve this problem are often used in sort algorithms or to find the median of a set. These can be easily changed to find the kth largest element.

Author: VZ


Vladimir Zabrodsky's analysis and comparison (Rexx)
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Entry modified 2 March 2015.
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Cite this as:
Vladimir Zabrodsky, "select and partition", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 2 March 2015. (accessed TODAY) Available from: