100274. 斐波那契数

难度: Easy

题目描述

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解题思路

代码实现

解决方案

java

class Solution {
    public int fib(int n) {

        int mod = 1000000007;
        if (n == 0) {
            return 0;
        }
        if (n == 1) {
            return 1;
        }

        int first = 0;
        int second = 1;

        for (int i = 2; i <= n; i++) {
            int temp = (first + second) % mod;
            first = second;
            second = temp;
        }

        return second;

    }
}