7、斐波那契数列

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，第1项是1）。 

n<=39

===================Python================

# -*- coding:utf-8 -*-
class Solution:
    def Fibonacci(self, n):
        # write code here
        a, b = 0, 1
        if n == 0:
            return 0
        for i in range(1, n+1):
            a, b = b, a+b
        return a

======================Java=====================

public class Solution {
    public int Fibonacci(int n) {
        int a = 0;
        int b = 1;
        if (n == 0) return 0;
        for (int i = 1; i <= n; i++){
            int tmp = a;
            a = b;
            b = tmp + b;
        }
        return a;
    }
}