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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