斐波那契数列非递归算法

class Solution {
public:
    int Fibonacci(int n) {
		int res[2] = {0,1};
        if(n<=1)
            return res[n];
        
        int num1 = 1;
        int num2 = 0;
        int sum = 0;
        
       	for(int i = 2;i<=n;i++)
        {
			sum = num1+num2;
            num2 = num1;
            num1 = sum;
        }
        
        return sum;
    }
};