2348. Number of Zero-Filled Subarrays

For each number, we want to extend the streak, and extend all subarrays that end at this point. Then we add that to the total count, and return it.

class Solution:
    def zeroFilledSubarray(self, nums: List[int]) -> int:
	    total = 0
	    for val, group in groupby(nums):
	        if val == 0:  
	            streak = len(list(group))
	            total += streak * (streak + 1) // 2
	    return total