Find the subarray (continuous subsequence) with max sum or its sum

max_subarray.py

def max_subarray_naive(a: list) -> int:
    """ takes O(n^2) time
        just sum all of the subarrays
    """
    m = a[0] if len(a) > 0 else 0
    for i in range(len(a)):
        for j in range(i, len(a)):
            m = max(m, sum(a[i:j]))
    return m


def max_subarray_smart(a: list) -> int:
    """
    """
    def max_subarray_iter(a: list, begin: int, end: int):
        pass
    
    def max_subarray_with_index(a: list, i: int):
        pass
    
    return max_subarray_iter(a, 0, len(a))


def max_subarray_dynamic(a: list) -> int:
    """
    """
    pass