Number of subarrays with gcd equal to k

Array Math Number Theory

52.4% acceptance

Feb 25, 2026

463

Given an integer array nums and an integer k, return the number of subarrays of nums where the greatest common divisor of the subarray's elements is k. * A subarray is a contiguous non-empty sequence of elements within an array. The greatest common divisor of an array is the largest integer that evenly di vides all the array elements. *

Solution

Rust

Time O(n²)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn subarray_gcd(nums: Vec<i32>, k: i32) -> i32 {
    fn gcd(a: i32, b: i32) -> i32 { if b == 0 { a } else { gcd(b, a % b) } }
    let n = nums.len();
    let mut count = 0;
    for i in 0..n {
      let mut g = 0;
      for j in i..n {
        g = gcd(g, nums[j]);
        if g == k { count += 1; }
        if g < k { break; }
      }
    }
    count
  }
}