[LeetCode] Problem 643 - Maximum Average Subarray I

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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

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].

Code

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public double findMaxAverage(int[] nums, int k) {
    int max = Integer.MIN_VALUE;
    int sum = 0;

    for (int i = 0; i < nums.length; i++) {
        sum += nums[i];

        if (i >= k)
            sum -= nums[i - k];

        if (i >= k - 1)
            max = Math.max(max, sum);
    }

    return max * 1.0 / k;
}