Given an array arr[] and an integer K where K is smaller than size of array, the task is to find the K^{th} smallest element in the given array. It is given that all array elements are distinct.
Note :- l and r denotes the starting and ending index of the array.
Example 1:
Input:
N = 6
arr[] = 7 10 4 3 20 15
K = 3
Output : 7
Explanation :
3rd smallest element in the given
array is 7.
Example 2:
Input:
N = 5
arr[] = 7 10 4 20 15
K = 4
Output : 15
Explanation :
4th smallest element in the given
array is 15.
Your Task:
You don't have to read input or print anything. Your task is to complete the function kthSmallest() which takes the array arr[], integers l and r denoting the starting and ending index of the array and an integer K as input and returns the K^{th} smallest element.

Expected Time Complexity: O(n)
Expected Auxiliary Space: O(log(n))
Constraints:
1 <= N <= 10^{5}
1 <= arr[i] <= 10^{5}
1 <= K <= N

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