快速排序

package algorithm.sort;

public class QuickSort {

    public

static void main(String[] args) {

       int[] a =

new int[] {5, 3, 7, 2, 1, 4, 9, 8, 6, 1};

       sort(a);

       print(a);

    }

static void sort(int[] a)

{

       sort(a, 0,

a.length - 1);

static void sort(int[] a,

int p, int r) {

       if (p <

r) {

int q = partition(a, p, r);

sort(a, p, q - 1);

sort(a, q + 1, r);

       }

    private

static int partition(int[] a,

       int x =

a[p];

       int i =

p;

       for

(int j = p + 1; j <= r; j++) {

if (a[j] <= x) {

i++;

exchange(a, i, j);

}

       exchange(a, i,

p);

       return

i;

static void exchange(int[] a,

int i1, int i2) {

       int tmp =

a[i1];

       a[i1] = a[i2];

       a[i2] = tmp;

static void print(int[] a)

       if (a ==

null || a.length == 0)

return;

(int i = 1; i <= a.length; i++) {

System.out.print(a[i - 1] + "\t");

if (i % 5 == 0)

System.out.println();