2261. 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.

class Solution {
public:
    int countDistinct(vector<int>& nums, int k, int p) {
        unordered_set<string> vis;
        int n = nums.size(), res = 0;
        for(int i = 0; i < n; i++) {
            int j = i;
            string key = "";
            for(int c = 0; c <= k and j < n; j++) {
                if(nums[j] % p == 0) c++;
                if(c <= k) {
                    key += to_string(nums[j]) + "#";
                    if(vis.insert(key).second)
                        res++;
                }
            }
        }
        return res;
    }
};