HTMLify

class Solution:
    def countAtMostK(self, arr, k):
        if k == 0:
            return 0
        
        n = len(arr)
        left = 0
        right = 0
        count = 0
        freq = {}
        
        while right < n:
            freq[arr[right]] = freq.get(arr[right], 0) + 1
            
            while len(freq) > k:
                freq[arr[left]] -= 1
                if freq[arr[left]] == 0:
                    del freq[arr[left]]
                left += 1
            
            count += (right - left + 1)
            right += 1
            
        return count