java实现快速排序（利用随机索引）

 public void random_partion(int start, int length) {//核心代码（随机位置二分排序）        if (length <= 1)            return;        Random rand = new Random();        int index = rand.nextInt(length) + start;        int i = start - 1;        int j = start;        // System.out.println("start--->"+start+"length--->"+length+"i--->"+i+"j--->"+j+"index--->"+index+"start+length-1--->"+(start+length-1));        this.swap(index, start + length - 1);        for (j = start; j < start + length; j++) {            if (initArray[j] < initArray[start + length - 1]) {                this.swap(++i, j);            }        }        this.swap(++i, start + length - 1);        random_partion(start, i - start + 1);        random_partion(i + 1, length + start - i - 1);    }    public int[] quickSorted() {        this.random_partion(0, initArray.length);        return initArray;    }public void swap(int a, int b) {        int temp = initArray[a];        initArray[a] = initArray[b];        initArray[b] = temp;    }