Formatted question description: https://leetcode.ca/all/643.html

643. Maximum Average Subarray I (Easy)

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].

Companies:
Amazon

Related Topics:
Array

Similar Questions:

Solution 1.

// OJ: https://leetcode.com/problems/maximum-average-subarray-i/

// Time: O(N)
// Space: O(1)
class Solution {
public:
    double findMaxAverage(vector<int>& nums, int k) {
        int sum = 0, maxSum = INT_MIN;
        for (int i = 0; i < nums.size(); ++i) {
            if (i < k) {
                sum += nums[i];
                if (i == k - 1) maxSum = sum;
            } else {
                sum += nums[i] - nums[i - k];
                maxSum = max(maxSum, sum);
            }
        }
        return (double)maxSum / k;
    }
};

Java

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

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