def findMaxAverage(self, nums, k):

"""

def getDelta(avg, nums, k):

accu = [0.0] * (len(nums) + 1)

minval_pos = None

delta = 0.0

for i in xrange(len(nums)):

accu[i+1] = nums[i] + accu[i] - avg

if i >= (k-1):

if minval_pos == None or accu[i-k+1] < accu[minval_pos]:

minval_pos = i-k+1

if accu[i+1] - accu[minval_pos] >= 0:

delta = max(delta, (accu[i+1] - accu[minval_pos]) / (i+1 - minval_pos))

return delta

left, delta = min(nums), float("inf")

while delta > 1e-5:

delta = getDelta(left, nums, k)

left += delta