题解 | #跳台阶扩展问题#

#include <vector>
class Solution {
public:
    int jumpFloorII(int number) {
        //递推公式f(n)=f(n-1)+f(n-2)+f(n-3)+…+f(1) 推导出f(n)=f(n-1)*2
        if (number == 1) 
        {
            return 1;
        }

        if (number == 2) 
        {
            return 2;
        }

        vector<int> dp(number + 1,0);
        dp[1] = 1;
        dp[2] = 2;
        for(int i = 3;i < number + 1; i++)
        {
            dp[i] = dp[i-1] * 2;
        }

        return dp[number];
    }
};