python递归与非递归实现斐波那契数列

1.题目描述

大家都知道斐波那契数列，现在要求输入一个整数n，请你输出斐波那契数列的第n项（从0开始，第0项为0）。

递归实现：

class Solution():
    def Fibnacci(self,n):
        if n <= 0:
            return 0
        if n == 1:
            return 1
        return self.Fibnacci(n-1) + self.Fibnacci(n-2)

 非递归实现：

def Fibnacci(n):
    result = [0,1]
    if n <= 1:
        return result[n]
    for i in range(2,n+1):
        result.append(result[i-1]+result[i-2])
    return result[n]

2.题目描述 一只青蛙一次可以跳上1级台阶，也可以跳上2级。求该青蛙跳上一个n级的台阶总共有多少种跳法（先后次序不同算不同的结果）。

[2. Tímù miáoshù yī zhǐ qīngwā yīcì kěyǐ tiào shàng 1 jí táijiē, yě kěyǐ tiào shàng 2 jí. Qiú gāi qīngwā tiào shàng yīgè n jí de táijiē zǒnggòng yǒu duōshǎo zhǒng tiào fǎ (xiānhòu cìxù bùtóng suàn bùtóng de jiéguǒ).]

2. Description of the topic
A frog can jump to the first step or jump to the second level. Ask the frog to jump on an n-level step in total how many kinds of jumps (the order is different).