[NK]斐波那契数列

斐波那契数列
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）。
n<=39

#include "stdafx.h"
#include <iostream>
using namespace std;

class Solution {
public:
    /*递归超过内存限制
    int Fibonacci(int n) {
        if (n == 0)
        {
            return 0;
        }
        if (n == 1 || n == 2)
        {
            return 1;
        }
        else
        {
            return Fibonacci(n - 1) + Fibonacci(n - 2);
        }
    }
    */
    int Fibonacci(int n)
    {
        if (n == 0)
        {
            return 0;
        }
        if (n == 1 || n == 2)
        {
            return 1;
        }
        int i;
        int result1 = 1;
        int result2 = 1;
        int tmp;
        for (int i = 3; i <= n; i++)
        {
            tmp = result1;
            result1 = result1 + result2;
            result2 = tmp;
        }
        return result1;
    }

};

int main()
{
    Solution *s = new Solution();
    cout << s->Fibonacci(2) << endl;
    cout << s->Fibonacci(5) << endl;
    cout << s->Fibonacci(6) << endl;
    return 0;
}