快排

思路：

https://blog.youkuaiyun.com/u014241071/article/details/81565148

他写的比我好，我还是只上代码吧。

//快排
	public static int[] sortArray(int[] nums) {
		int left = 0;
		int right = nums.length-1;
		quickSort(nums,left,right);
		return nums;
	}
	private static void quickSort(int[] nums, int left, int right) {
		// TODO Auto-generated method stub
		if(left<right) {
			int mid = getMiddle(nums,left,right);
			quickSort(nums, left, mid-1);
			quickSort(nums, mid+1, right);
		}
	}
	private static int getMiddle(int[] nums, int left, int right) {
		// TODO Auto-generated method stub
		int i = left;
		int j = right;
		int temp = nums[left];
		while(i<j) {
			while(i<j&&temp<=nums[j]) {
				j--;
			}
			while(i<j&&temp>=nums[i]) {
				i++;
			}
			if(i<j) {
				int l = nums[i];
				int r = nums[j];
				nums[i] = r;
				nums[j] = l;
			}
		}
		nums[left] = nums[i];
		nums[i] = temp;
		
		return i;
	}