quickselect

A tiny and fast selection algorithm in JavaScript (specifically, Floyd-Rivest selection).

quickselect(array,k[,left,right,compareFn]);

Rearranges items so that all items in the [left, k] are the smallest. The k-th element will have the (k - left + 1)-th smallest value in [left, right].

• array: the array to partially sort (in place)
• k: middle index for partial sorting (as defined above)
• left: left index of the range to sort (0 by default)
• right: right index (last index of the array by default)
• compareFn: compare function

Example:

constarr=[65,28,59,33,21,56,22,95,50,12,90,53,28,77,39];quickselect(arr,8);// arr is [39, 28, 28, 33, 21, 12, 22, 50, 53, 56, 59, 65, 90, 77, 95]// ^^ middle index