"""Return the sum of the numbers in the array, returning 0 for an empty array. Except the number 13 is very unlucky, so it does not count and numbers that come immediately after a 13 also do not count.


sum13([1, 2, 2, 1]) → 6
sum13([1, 1]) → 2
sum13([1, 2, 2, 1, 13]) → 6"""


def sum13(nums):
    if len(nums) == 0:
        return 0

    for i in range(0, len(nums)):

        if nums[i] == 13:
            nums[i] = 0
            if i + 1 < len(nums):
                nums[i + 1] = 0
    return sum(nums)


print (sum13([1, 2, 2, 1, 13]))
print (sum13([1, 1]))
print (sum13([1, 2, 2, 1]))
print (sum13([1, 2, 13, 2, 1, 13]))
print (sum13([13, 0, 13]))



