3708. Longest Fibonacci Subarray

You are given an array of positive integers nums.

A Fibonacci array is a contiguous sequence whose third and subsequent terms each equal the sum of the two preceding terms.

Return the length of the longest Fibonacci subarray in nums.

Note: Subarrays of length 1 or 2 are always Fibonacci.

class Solution {
public:
    int longestSubarray(vector<int>& nums) {
        long long res = 0, now = 2;
        for(int i = 0; i + 2 < nums.size(); i++) {
            long long expect = nums[i] + nums[i+1];
            now = nums[i+2] == expect ? now + 1 : 2;
            res = max(res, now);
        }
        return res;
    }
};