剑指offer---变态跳台阶

class Solution
{
public:
    int jumpFloorII(int number)
    {
        if (number == 1)
        {
            return 1;
        }
        else if (number == 2)
        {
            return 2;
        }
        else
        {
            return(2 * jumpFloorII(number - 1));
        }
    }
        
};