Code RoomLongest subarray GCD
HardPrep Room Coding #975

Longest subarray GCD

CodingAlgorithms & data structuresSenior–Staff~35 min

Given a list of positive integers (length 1 to 2e5, each 1 <= x <= 1e9), return the length of the longest contiguous subarray whose GCD is strictly greater than 1. If no such subarray exists, return 0. A single element x > 1 counts as a length-1 subarray. The O(n^2) approach is too slow; aim for O(n log(maxval)).

Implement
longest_gcd_subarray(nums: list[int]) → int
Examples
in[[2,4,6,3,9,12]]out4
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 35 min
InputExpectedGot
[[2,4,6,3,9,12]]4not run yetsample