README_EN.md

643. Maximum Average Subarray I

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Description

Given an array consisting of n integers, find the contiguous subarray of given length k that has the maximum average value. And you need to output the maximum average value.

Example 1:

Input: [1,12,-5,-6,50,3], k = 4

Output: 12.75

Explanation: Maximum average is (12-5-6+50)/4 = 51/4 = 12.75

 

Note:

1. 1 <= k <= n <= 30,000.
2. Elements of the given array will be in the range [-10,000, 10,000].

 

Solutions

Slide window.

Python3

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

Java

class Solution {
    public double findMaxAverage(int[] nums, int k) {
        int s = 0;
        for (int i = 0; i < k; ++i) {
            s += nums[i];
        }
        int ans = s;
        for (int i = k; i < nums.length; ++i) {
            s += (nums[i] - nums[i - k]);
            ans = Math.max(ans, s);
        }
        return ans * 1.0 / k;
    }
}

TypeScript

function findMaxAverage(nums: number[], k: number): number {
    let n = nums.length;
    let ans = 0;
    let sum = 0;
    // 前k
    for (let i = 0; i < k; i++) {
        sum += nums[i];
    }
    ans = sum;
    for (let i = k; i < n; i++) {
        sum += nums[i] - nums[i - k];
        ans = Math.max(ans, sum);
    }
    return ans / k;
}

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