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Abhishek Chaudhary
Abhishek Chaudhary

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K Divisible Elements Subarrays

Given an integer array nums and two integers k and p, return the number of distinct subarrays which have at most k elements divisible by p.

Two arrays nums1 and nums2 are said to be distinct if:

  • They are of different lengths, or
  • There exists at least one index i where nums1[i] != nums2[i].

A subarray is defined as a non-empty contiguous sequence of elements in an array.

Example 1:

Input: nums = [2,3,3,2,2], k = 2, p = 2
Output: 11
Explanation:
The elements at indices 0, 3, and 4 are divisible by p = 2.
The 11 distinct subarrays which have at most k = 2 elements divisible by 2 are:
[2], [2,3], [2,3,3], [2,3,3,2], [3], [3,3], [3,3,2], [3,3,2,2], [3,2], [3,2,2], and [2,2].
Note that the subarrays [2] and [3] occur more than once in nums, but they should each be counted only once.
The subarray [2,3,3,2,2] should not be counted because it has 3 elements that are divisible by 2.

Example 2:

Input: nums = [1,2,3,4], k = 4, p = 1
Output: 10
Explanation:
All element of nums are divisible by p = 1.
Also, every subarray of nums will have at most 4 elements that are divisible by 1.
Since all subarrays are distinct, the total number of subarrays satisfying all the constraints is 10.

Constraints:

  • 1 <= nums.length <= 200
  • 1 <= nums[i], p <= 200
  • 1 <= k <= nums.length

SOLUTION:

class Solution:
    def countDistinct(self, nums: List[int], k: int, p: int) -> int:
        subs = set()
        left, right, divs = 0, 0, 0
        while right < len(nums):
            if nums[right] % p == 0:
                divs += 1
            while divs > k and left < right:
                if nums[left] % p == 0:
                    divs -= 1
                left += 1
            for l in range(left, right + 1):
                subs.add(tuple(nums[l:right + 1]))
            right += 1
        return len(subs)
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