LeetCode: Maximum Average Subarray I Solution

Approach: Sliding window

Init a sum of contiguous subarray of [0, k]

On every next slide, add the current iterated number and subtract the previous begin range

For example, sum of [1, k + 1] will be sum([0, k]) - nums[0] + nums[k + 1]

Implementation

1var findMaxAverage = function (nums, k) {
2  // init sum
3  let sum = 0
4  for (let i = 0; i < k; i++) {
5    sum += nums[i]
6  }
7
8  // slide window
9  let max = sum
10  for (let i = k; i < nums.length; i++) {
11    sum = sum + nums[i] - nums[i - k]
12    max = Math.max(max, sum)
13  }
14
15  return max / k
16}