Maximum sum subarray

Ref: http://www.geeksforgeeks.org/largest-sum-contiguous-subarray/

Notes:

Algorithm doesn't work for all negative numbers. It simply returns 0 if all numbers are negative. For handling this we can add an extra phase before actual implementation. The phase will look if all numbers are negative, if they are it will return maximum of them (or smallest in terms of absolute value).

'''
This solution does not deal with -ve numbers. This is Kadane's algorith
'''
# Function to find the maximum contiguous subarray
def maxSubArraySum(a,size):

    max_so_far = 0
    max_ending_here = 0

    for i in range(0, size):
        max_ending_here = max_ending_here + a[i]
        if max_ending_here < 0:
            max_ending_here = 0

        # Do not compare for all elements. Compare only   
        # when  max_ending_here > 0
        elif (max_so_far < max_ending_here):
            max_so_far = max_ending_here

    return max_so_far

'''
This will also deal with -ve numbers and a more compact version
'''
def maxSubArraySum(a,size):

    max_so_far =a[0]
    curr_max = a[0]

    for i in range(1,size):
        curr_max = max(a[i], curr_max + a[i])
        max_so_far = max(max_so_far,curr_max)

    return max_so_far