max_sum
as the sum of the first k
elements.window_sum
with the same value as max_sum
.k
to the end of the array.
a. Update window_sum
by subtracting the element that is left out of the window (nums[i - k]
) and adding the new element that enters the window (nums[i]
).
b. Update max_sum
with the maximum of max_sum
and the new window_sum
.max_sum / k
as the maximum average.