LeetCode 2958: Length of Longest Subarray With at Most K Frequency

Meta Data

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Difficulty: medium First Attempt: 2026-01-10

• Submissions: Accepted (first try)

Approach

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The same template as LeetCode 3090, with the limit k instead of 2 and integers instead of characters.

After adding x on the right, only x can exceed k, so shrink the left until it is back to k.

My Solution

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class Solution:
    def maxSubarrayLength(self, nums: List[int], k: int) -> int:
        cnt = Counter()
        left = best = 0
        for right, x in enumerate(nums):
            cnt[x] += 1
            while cnt[x] > k:
                cnt[nums[left]] -= 1
                left += 1
            best = max(best, right - left + 1)
        return best

Complexity

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Time O(n), space O(n).

Mistakes to Avoid

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• Writing the shrink condition on the left element: check the newly added x.

Interview Explanation

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A longest-window slide where each number appears at most k times. After adding x on the right only x can exceed, so I shrink the left until x is back to k and track the longest length. Time O(n).