10-1-斐波拉契数列

leetcode 链接：https://leetcode-cn.com/problems/fei-bo-na-qi-shu-lie-lcof/

题目

解答

class Solution {
    public int fib(int n) {
        if (n < 2) {
            return n;
        }
        int x = 0;
        int y = 1;
        for (int i = 1; i < n; i++){
            y = x + y;
            x = y - x;
            // 或者：y %= 1000000007;
            y = y > 1000000007 ? (y - 1000000007) : y;
        }
        return y;
    }
}