Longest fibonacci subarray

Array

69.5% acceptance

Feb 24, 2026

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.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn longest_subarray(nums: Vec<i32>) -> i32 {
    let n = nums.len();
    if n < 3 { return n as i32; }
    let mut max_len = 2;
    let mut len = 2;
    for i in 2..n {
      if (nums[i - 2] as i64) + (nums[i - 1] as i64) == nums[i] as i64 {
        len += 1;
      } else {
        len = 2;
      }
      max_len = max_len.max(len);
    }
    max_len
  }
}