剑指offer

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

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

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