448. 找到所有数组中消失的数字

class Solution {
    public List<Integer> findDisappearedNumbers(int[] nums) {
        Arrays.sort(nums);
        int i = 0, j = 1;
        List<Integer> list = new ArrayList<Integer>();
        while(i < nums.length)
        {
            if(nums[i] == j)
            {
                i++;
                j++;
            }
            else if(nums[i] < j)
            {
                i++;
            }
            else
            {
                list.add(j);
                j++;
            }
        }
        while(j <= nums.length)
        {
            list.add(j);
            j++;
        }
        return list;
    }
}