largest_subarray_sum.py

from sys import maxsize


def max_sub_array_sum(a: list, size: int = 0):
 """
 >>> max_sub_array_sum([-13, -3, -25, -20, -3, -16, -23, -12, -5, -22, -15, -4, -7])
 -3
 """
 size = size or len(a)
 max_so_far = -maxsize - 1
 max_ending_here = 0
 for i in range(0, size):
 max_ending_here = max_ending_here + a[i]
 if max_so_far < max_ending_here:
 max_so_far = max_ending_here
 if max_ending_here < 0:
 max_ending_here = 0
 return max_so_far


if __name__ == "__main__":
 a = [-13, -3, -25, -20, 1, -16, -23, -12, -5, -22, -15, -4, -7]
 print(("Maximum contiguous sum is", max_sub_array_sum(a, len(a))))