Maximum Average Subarray I

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.

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

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number}
 */
var findMaxAverage = function(nums, k) {
    let currentSum = 0;

    for (let i = 0; i < k; i++) {
        currentSum += nums[i];
    }

    let maxSum = currentSum;

    for (let i = k; i < nums.length; i++) {
        currentSum += nums[i] - nums[i - k];
        maxSum = Math.max(maxSum, currentSum);
    }

    return maxSum / k;
};