Watch 10 video solutions for Count Array Pairs Divisible by K, a hard level problem involving Array, Math, Number Theory. This walkthrough by Techdose has 26,108 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Given a 0-indexed integer array nums of length n and an integer k, return the number of pairs (i, j) such that:
0 <= i < j <= n - 1 andnums[i] * nums[j] is divisible by k.
Example 1:
Input: nums = [1,2,3,4,5], k = 2 Output: 7 Explanation: The 7 pairs of indices whose corresponding products are divisible by 2 are (0, 1), (0, 3), (1, 2), (1, 3), (1, 4), (2, 3), and (3, 4). Their products are 2, 4, 6, 8, 10, 12, and 20 respectively. Other pairs such as (0, 2) and (2, 4) have products 3 and 15 respectively, which are not divisible by 2.
Example 2:
Input: nums = [1,2,3,4], k = 5 Output: 0 Explanation: There does not exist any pair of indices whose corresponding product is divisible by 5.
Constraints:
1 <= nums.length <= 1051 <= nums[i], k <= 105