LeetCode 643: Maximum Average Subarray I

Meta Data

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Difficulty: easy First Attempt: 2025-08-02

• Total time: 00:00.00

Intuition

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This is a fixed window size sliding window problem. Given the problem requirements, we need to find the maximum average of a subarray. We can understand this as finding the maximum sum of a subarray and then dividing by the window size to get the average. Therefore, the target can be simplified to a maximum subarray sum problem.

Approach

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class Solution:
    def findMaxAverage(self, nums: List[int], k: int) -> float:
        max_sum = 0
        for i in range(k):
            max_sum += nums[i]

        sum_now = max_sum
        for i in range(k, len(nums)):
            sum_now += nums[i]
            sum_now -= nums[i - k]

            max_sum = max(max_sum, sum_now)

        return max_sum / k

Findings

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This is a fixed window problem. We can accumulate the first window first, and then slide the window until the end.

Encountered Problems

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