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。

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C++

class Solution {public:    int Fibonacci(int n) {        int a[3] = {0,1};        if(n<=0)            return 0;        else if(n == 1)            return 1;        else        {            for(int i=2; i <= n; i++)            {                a[2] = a[0]+a[1];                a[0] = a[1];                a[1] = a[2];            }        }        return a[2];       }};

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Java

public class Solution {    public int Fibonacci(int n) {        int[] dp = {0,1,1};        if(n<=0)            return dp[0];        else if(n == 1)            return dp[1];        else        {            for(int i = 2; i <= n; i++)            {                dp[2] = dp[0] + dp[1];                dp[0] = dp[1];                dp[1] = dp[2];             }        }        return dp[2];    }}

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Python

# -*- coding:utf-8 -*-class Solution:    def Fibonacci(self, n):        # write code here        a = [0,1]        if n < 2:            return a[n]        else:            for i in range(2,n+1):                a.append(a[i-1]+a[i-2])            return a[n]