Simple implementation of maximum subarray (divide-and-conquer) in python

maximum subarray.py

def findMaxCrossingSubArray(lst, low, high, mid):
    l, h = 0, 0
	i = mid
	s = 0
	leftsum = lst[i] - 1
	while i >= low:
		s = s + lst[i]
		if s > leftsum:
			leftsum = s
			l = i
		i = i - 1
	j = mid + 1
	s = 0
	rightsum = lst[j] - 1
	while j <= high:
		s = s + lst[j]
		if s > rightsum:
			rightsum = s
			h = j
		j = j + 1
	return (l, h, leftsum + rightsum)

def findMaxSubArray(lst, low, high):
	if low == high:
		return (low, high, lst[low])
	mid = (low + high) / 2
	llow, lhigh, leftSum = findMaxSubArray(lst, low, mid)
	rlow, rhigh, rightSum = findMaxSubArray(lst, mid + 1, high)
	clow,chigh, crossingSum = findMaxCrossingSubArray(lst, low, high, mid)
	if leftSum > rightSum:
		if leftSum > crossingSum:
			return (llow, lhigh, leftSum)
		else:
			return (clow, chigh, crossingSum)
	else:
		if rightSum > crossingSum:
			return (rlow, rhigh, rightSum)
		else:
			return (clow, chigh, crossingSum)