LeetCode/2348_Number_of_Zero_Filled_Subarrays.py at main · AnmolPatel20/LeetCode · GitHub

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"""
Given an integer array nums, return the number of subarrays filled with 0.

A subarray is a contiguous non-empty sequence of elements within an array.


Example 1:

Input: nums = [1,3,0,0,2,0,0,4]
Output: 6
Explanation:
There are 4 occurrences of [0] as a subarray.
There are 2 occurrences of [0,0] as a subarray.
There is no occurrence of a subarray with a size more than 2 filled with 0. Therefore, we return 6.
Example 2:

Input: nums = [0,0,0,2,0,0]
Output: 9
Explanation:
There are 5 occurrences of [0] as a subarray.
There are 3 occurrences of [0,0] as a subarray.
There is 1 occurrence of [0,0,0] as a subarray.
There is no occurrence of a subarray with a size more than 3 filled with 0. Therefore, we return 9.
Example 3:

Input: nums = [2,10,2019]
Output: 0
Explanation: There is no subarray filled with 0. Therefore, we return 0.


Constraints:

1 <= nums.length <= 105
-109 <= nums[i] <= 109

"""

class Solution:
    def zeroFilledSubarray(self, nums):
        ans = 0
        n = len(nums)
        curr = 0
        for i in range(n):
            if nums[i] == 0:
                curr += 1
            else:
                ans += curr * (curr + 1) // 2
                curr = 0
        ans += curr * (curr + 1) // 2
        return ans