992. Subarrays with K Different Integers
Given an integer array nums and an integer k, return the number of good subarrays of nums.
A good array is an array where the number of different integers in that array is exactly k.
- For example, [1,2,3,1,2] has 3 different integers: 1, 2, and 3.
A subarray is a contiguous part of an array.
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| class Solution { public: int subarraysWithKDistinct(vector<int>& nums, int k) { return atMostK(nums, k) - atMostK(nums, k - 1); } int atMostK(vector<int>& nums, int k) { unordered_map<int, int> counter; int res = 0; for(int l = 0, r = 0; r < nums.size(); r++) { if(counter[nums[r]]++ == 0) k--; while(k < 0) { if(counter[nums[l]]-- == 1) k++; l++; } res += r - l; } return res; } };
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