Java 代码

class Solution 
{
    public int getMissingNumber(int[] nums) 
    {
        if (nums.length == 0)
            return 0;

        int x = -1;

        for (int i = 0; i < nums.length; i ++)
        {
            if (nums[i] != i)
            {
                x = i;
                break;
            }
        }

        if (x == -1)
            return nums.length;
        else
            return x;
    }
}