算法习题03：快速排序

算法图解：快速排序

截图来自《算法图解》这本书

代码实现：

public class QuickUtil {

    public static int[] quickSort(int[] ints, int start, int end){
        if (start > end){
            return ints;
        }
        //基点，第一个数
        int pivot = ints[start];
        //左指针
        int left = start;
        int right = end;
        while (left < right){
            while (ints[right] >= pivot && left < right){
                right --;
            }
            while (ints[left] <= pivot && left < right){
                left ++;
            }
            if (left < right){
                int temp = ints[right];
                ints[right] = ints[left];
                ints[left] = temp;
            }
        }
        ints[start] = ints[left];
        ints[left] = pivot;
        quickSort(ints, start, left -1);
        quickSort(ints, left + 1, end);
        return ints;
    }

    public static void main(String[] args) {
        int[] arr = {81, 65, 17, 1, 71, 9, 26, 12, 93, 30, 55};
        int[] ints = quickSort(arr, 0, arr.length - 1);
        System.out.println(JSON.toJSONString(ints));
    }
}