Maximum Average Subarray I

Sliding Window Technique

• Calculate the sum of the first `k` elements and store it in `subArray`.
• Initialize the maximum average `avg` as `subArray / k`.
• Iterate from index `k` to the end of the array:
• - At each step, update the sum by adding the new element and subtracting the element that is sliding out of the window: `subArray = subArray + nums[i] - nums[i - k]`.
• - Recalculate the average and update `avg` if it's higher.
• Return the final maximum average rounded to 5 decimal places.

// 🔹 JavaScript Solution using Sliding Window
var findMaxAverage = function(nums, k) {
  let subArray = 0;
  for (let i = 0; i < k; i++) {
    subArray += nums[i];
  }
  let avg = subArray / k;

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

  return avg.toFixed(5);
};

console.log(findMaxAverage([1, 12, -5, -6, 50, 3], 4)); // Output: 12.75000
console.log(findMaxAverage([5], 1)); // Output: 5.00000