[Leetcode]643. Maximum Average Subarray I

📄 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

💻 My Submission

class Solution:
    def findMaxAverage(self, nums: List[int], k: int) -> float:
        _sum=sum(nums[:k])
        max_avg=_sum/k
        
        for i in range(len(nums)-k):
            _sum=_sum-nums[i]+nums[i+k]
            window_avg=_sum/k
            max_avg=max(max_avg,window_avg)
        
        return max_avg

❓ How to solve the problem

• find the maximum K-length sum
• After, we can divide by K to get the average.

Clean version of my submission

class Solution:
    def findMaxAverage(self, nums: List[int], k: int) -> float:
        _sum=max_sum=sum(nums[:k])
        
        for i in range(len(nums)-k):
            _sum=_sum-nums[i]+nums[i+k]
            max_sum=max(max_sum,_sum)
        
        return max_sum/k

References

• https://leetcode.com/problems/maximum-average-subarray-i/discuss/105469/Python-Straightforward-with-Explanation