Find the maximal sum of any double slice.

MaxDoubleSliceSum.py

def solution(A):
    # write your code in Python 2.7
    n = len(A)
    if n <=3:
        return 0
    leftMax = [0]*n
    rightMax = [0]*n
    for i in xrange(2,n-1):
        leftMax[i] = max(0,leftMax[i-1]+A[i-1])
    for i in xrange(n-3,0,-1):
        rightMax[i] = max(0, rightMax[i+1]+A[i+1])
    Max = 0
    #print leftMax
    #print rightMax
    for i in xrange(n):
        s = leftMax[i]+rightMax[i]
        if s > Max:
            Max=s
            
    return Max