Kth Smallest Element in the Array

Problem Description

Find the B^th smallest element in an unsorted array of non-negative integers A.
Definition of kth smallest element: The k^th smallest element is the minimum possible n such that there are at least k elements in the array <= n.
In other words, if the array A was sorted, then Ak - 1

NOTE: You are not allowed to modify the array (The array is read-only). Try to do it using constant extra space.

Problem Constraints

1 <= |A| <= 10⁶

1 <= B <= |A|

1 <= A[i] <= 10⁹

Input Format

The first argument is an integer array A.

The second argument is integer B.

Output Format

Return the B^th smallest element in given array.

Example Input

Input 1:

A = [2, 1, 4, 3, 2]
B = 3

Input 2:

A = [1, 2]
B = 2

Example Output

Output 1:

Output 2:

Example Explanation

Explanation 1:

 3rd element after sorting is 2.

Explanation 2:

 2nd element after sorting is 2.

NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.

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Kth Smallest Element in the Array

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