剑指offer

class 
{
public:
    int jumpFloor(int number)
    {
        if (number <= 2) {
            return number;
        }

        int prev1, prev2, sum;
        prev1 = 1;
        prev2 = 2;
        sum = 0;

        for (int i = 3; i <= number; ++i)
        {
            sum = prev1 + prev2;
            prev1 = prev2;
            prev2 = sum;
        }

        return sum;
    }
};