643. Maximum Average Subarray I

You are given an integer array nums consisting of n elements, and an integer k

Example 1:

• Input: nums = [1,12,-5,-6,50,3], k = 4
• Output: 12.75000
• Explanation: Maximum average is (12 - 5 - 6 + 50) / 4 = 51 / 4 = 12.75

Example 2:

• Input: nums = [5], k = 1
• Output: 5.00000

Constraints:

• n == nums.length
• 1 <= k <= n <= 10^5
• -10^4 <= nums[i] <= 10^4

Solution

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

        for right in range(k, len(nums)):
            left = right - k
            window_sum -= nums[left]
            window_sum += nums[right]
            largest = max(largest, window_sum)

        return largest / k