快速排序

/**
 * 功能：快速排序
 */
public class QuickSort {

    public int[] process(int[] array) {

        if (null == array || 0 == array.length) {
            return array;
        }

        sort(array, 0, array.length - 1);

        return array;
    }

    public void sort(int[] array, int low, int high) {

        int middle; //枢纽的位置

        if (low < high) {
            middle = partition(array, low, high);
            sort(array, low, middle - 1);
            sort(array, middle + 1, high);
        }

    }

    public int partition(int[] array, int low, int high) {

        int midValue = array[low]; //存储枢纽的值

        while (low < high) {
            while (low < high && midValue <= array[high]) {
                high--;
            }

            swap(array, low, high);

            while (low < high && midValue >= array[low]) {
                low++;
            }

            swap(array, low, high);
        }

        return low;
    }

    public void swap(int[] array, int a, int b) {

        int temp;

        temp = array[a];
        array[a] = array[b];
        array[b] = temp;
    }
}