快速排序及其拓展

普通快排标准模板：

    private void quickSort(int[] nums, int left, int right){
        if(left < right){
            int pIdx = partition(nums, left, right);
            quickSort(nums, left, pIdx - 1);
            quickSort(nums, pIdx + 1, right);
        }
    }
    private int partition(int[] nums, int left, int right){
        int pivot = nums[left];
        while(left < right){
            while(left < right && nums[right] >= pivot){
                right--;
            }
            nums[left] = nums[right];
            while(left < right && nums[left] <= pivot){
                left++;
            }
            nums[right] = nums[left];
        }
        nums[left] = pivot;
        return left;