# LeetCode - 0509. Fibonacci Number
### 題目網址：https://leetcode.com/problems/fibonacci-number/
###### tags: `LeetCode` `Easy` `模擬`

/*
    -LeetCode format-
    Problem: 509. Fibonacci Number
    Difficulty: Easy
    
    by Inversionpeter
*/



class Solution {
public:
    int fib(int N) {
        int first = 0, second = 1, buffer;
        while (N--)
            buffer = first + second, first = second, second = buffer;
        return first;
    }
};