剑指offer | 变态跳台阶 | 03

目录

• 思路分析

思路分析

找规律

f(n)  =f(n-1)+f(n-2)+...+f(1)+1
f(n-1)=       f(n-2)+...+f(1)+1
f(n)=2f(n-1)

cpp

class Solution {
public:
    int jumpFloorII(int number) {
        int a=1;
        for(int i=1;i<number;i++){ // f(1)=1,这里没有f(0)
            a*=2;
        }
        return a;
    }
};

python

# -*- coding:utf-8 -*-
class Solution:
    def jumpFloorII(self, number):
        a=1
        for _ in range(1,number):
            a*=2
        return a