- Difficulty: Easy
- Tags: LeetCode, Easy, Array, leetcode-2176, Math, O(nlogk + n * sqrt(k)), O(n + sqrt(k))
Problem
Given a 0-indexed integer array
nums
of length n
and an integer k
, return the number of pairs (i, j)
where 0 <= i < j < n
, such that nums[i] == nums[j]
and (i \* j)
is divisible by k
.
Example 1:
Input: nums = [3,1,2,2,2,1,3], k = 2 Output: 4 Explanation: There are 4 pairs that meet all the requirements: - nums[0] == nums[6], and 0 * 6 == 0, which is divisible by 2. - nums[2] == nums[3], and 2 * 3 == 6, which is divisible by 2. - nums[2] == nums[4], and 2 * 4 == 8, which is divisible by 2. - nums[3] == nums[4], and 3 * 4 == 12, which is divisible by 2.
Example 2:
Input: nums = [1,2,3,4], k = 1 Output: 0 Explanation: Since no value in nums is repeated, there are no pairs (i,j) that meet all the requirements.
Constraints:
1 <= nums.length <= 100
1 <= nums[i], k <= 100