Quick

import java.util.Arrays;
import java.util.Random;

public class Main {

    public static void main(String[] args) {
        int[] a = createRandArr(200);
        quickSort(a, 0, a.length - 1);
        System.out.println(Arrays.toString(a));

    }

    private static int[] createRandArr(int n) {
        Random r = new Random();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = r.nextInt();
        }
        System.out.println(Arrays.toString(a));

        return a;
    }

    public static void quickSort(int[] arr, int l, int h) {
        if (l < h) {
            int n = h - l + 1;
            int med = kthSmallest(arr, l, h, n / 2);
            int p = partition(arr, l, h, med);

            quickSort(arr, l, p - 1);
            quickSort(arr, p + 1, h);
        }
    }

    static int findMedian(int[] arr, int i, int n) {
        Arrays.sort(arr, i, n);
        return arr[i + (n - i) / 2];
    }

    static int kthSmallest(int[] arr, int l, int r, int k) {
        if (k > 0 && k <= r - l + 1) {
            int n = r - l + 1;
            int i;
            int[] median = new int[(n + 4) / 5];
            for (i = 0; i < n / 5; i++)
                median[i] = findMedian(arr, l + i * 5, l + i * 5 + 5);

            if (i * 5 < n) {
                median[i] = findMedian(arr, l + i * 5, l + i * 5 + n % 5);
                i++;
            }

            int medOfMed = (i == 1) ? median[i - 1] :
                    kthSmallest(median, 0, i - 1, i / 2);

            int pos = partition(arr, l, r, medOfMed);

            if (pos - l == k - 1)
                return arr[pos];
            if (pos - l > k - 1)
                return kthSmallest(arr, l, pos - 1, k);
            return kthSmallest(arr, pos + 1, r, k - pos + l - 1);
        }
        return Integer.MAX_VALUE;
    }

    public static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static int partition(int[] arr, int l,int r, int x) {
        int i;
        for (i = l; i < r; i++)
            if (arr[i] == x)
                break;
        swap(arr, i, 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;
    }
}