Problem

Given an array 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
Example output: 12.75

Solution

// Solution:
// The solution is to iterate through the array and keep track of the sum of the first k elements.
// Then, for each subsequent element, subtract the first element of the previous subarray and add the current element.
// This way, we only have to iterate through the array once, and we don't have to create any new arrays.
// The time complexity is O(n) and the space complexity is O(1).

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