剑指07斐波那契数列

n<=39

class Solution {
public:
    int Fibonacci(int n) {
        int f=0,g=1;
        while (n--){
            g+=f;
            f=g-f;
        }
        return f;

    }
};

public class Solution {
    public int Fibonacci(int n) {
     int target=0;
        if (n==0)
            return 0;
        if (n==1)
            return 1;
        int one=0,two=1;
        for (int i=2;i<=n;i++){
            target=one+two;
            one=two;
            two=target;
        }
        return target;
    }
}

# -*- coding:utf-8 -*-
class Solution:
    def Fibonacci(self, n):
        # write code here
        f1=0
        f2=1
        for i in range(n):
            f1,f2=f2,f1+f2
        return f1