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643. Maximum Average Subarray I

Difficulty Topics

Description

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

Find a contiguous subarray whose length is equal to k that has the maximum average value and return this value. Any answer with a calculation error less than 10-5 will be accepted.

 

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 <= 105
  • -104 <= nums[i] <= 104

Solution

maximum-average-subarray-i.py
class Solution:
    def findMaxAverage(self, A: List[int], K: int) -> float:

        s = 0
        m = float('-inf')

        for i,x in enumerate(A):
            s += x

            if i >= K:
                s -= A[i-K]

            if i >= K-1:
                m = max(m, s)

        return m / K