Day 40 LeetCode 2799 Count Complete Subarrays in an Array.cpp

/*
2799. Count Complete Subarrays in an Array
Solved
Medium

You are given an array nums consisting of positive integers.
We call a subarray of an array complete if the following condition is satisfied:
The number of distinct elements in the subarray is equal to the number of distinct elements in the whole array.
Return the number of complete subarrays.
A subarray is a contiguous non-empty part of an array.

Example 1:
Input: nums = [1,3,1,2,2]
Output: 4
Explanation: The complete subarrays are the following: [1,3,1,2], [1,3,1,2,2], [3,1,2] and [3,1,2,2].

Example 2:
Input: nums = [5,5,5,5]
Output: 10
Explanation: The array consists only of the integer 5, so any subarray is complete. The number of subarrays that we can choose is 10.

Constraints:
1 <= nums.length <= 1000
1 <= nums[i] <= 2000
*/

class Solution {
  public:
    int countCompleteSubarrays(vector<int>& nums, int left = 0, int res = 0) {
        int k = unordered_set<int>(nums.begin(),nums.end()).size();
        unordered_map<int, int> mpp;

        for (int i = 0; i < nums.size(); ++i) {
            mpp[nums[i]]++;
            while (mpp.size() == k) {
                res += nums.size() - i;  
                mpp[nums[left]]--;
                if (mpp[nums[left]] == 0) mpp.erase(nums[left]);
                left++;
            }
        }
        return res;
    }
};