find Kth smallest

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public class KthSmallest {// This function returns k'th smallest element in arr[l..r]    // using QuickSort based method.  ASSUMPTION: ALL ELEMENTS    // IN ARR[] ARE DISTINCT    int kthSmallest(int arr[], int l, int r, int k)    {        // If k is smaller than number of elements in array        if (k > 0 && k <= r - l + 1)        {            // Partition the array around a random element and            // get position of pivot element in sorted array            int pos = randomPartition(arr, l, r);             // If position is same as k            if (pos-l == k-1)                return arr[pos];             // If position is more, recur for left subarray            if (pos-l > k-1)                return kthSmallest(arr, l, pos-1, k);             // Else recur for right subarray            return kthSmallest(arr, pos+1, r, k-pos+l-1);        }         // If k is more than number of elements in array        return Integer.MAX_VALUE;    }     // Utility method to swap arr[i] and arr[j]    void swap(int arr[], int i, int j)    {        int temp = arr[i];        arr[i] = arr[j];        arr[j] = temp;    }     // Standard partition process of QuickSort().  It considers    // the last element as pivot and moves all smaller element     // to left of it and greater elements to right. This function    // is used by randomPartition()    int partition(int arr[], int l, int r)    {        int x = arr[r], i = l;        for (int j = l; j <= r - 1; j++)        {            if (arr[j] <= x)            {                swap(arr, i, j);                i++;            }        }        swap(arr, i, r);        return i;    }     // Picks a random pivot element between l and r and     // partitions arr[l..r] arount the randomly picked     // element using partition()    int randomPartition(int arr[], int l, int r)    {        int n = r-l+1;        int pivot = (int)(Math.random()) % n;        swap(arr, l + pivot, r);        return partition(arr, l, r);    }     // Driver method to test above    public static void main(String args[])    {    KthSmallest ob = new KthSmallest();        int arr[] = {12, 3, 5, 7, 4, 19, 26};        int n = arr.length,k = 3;        System.out.println("K'th smallest element is "+                           ob.kthSmallest(arr, 0, n-1, k));    }}