2348. Number of Zero-Filled Subarrays

Description

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

Solutions

Solution 1

Python Code
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class Solution:
    def zeroFilledSubarray(self, nums: List[int]) -> int:
        ans = cnt = 0
        for v in nums:
            cnt = 0 if v else cnt + 1
            ans += cnt
        return ans

Java Code
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class Solution {
    public long zeroFilledSubarray(int[] nums) {
        long ans = 0;
        int cnt = 0;
        for (int v : nums) {
            cnt = v != 0 ? 0 : cnt + 1;
            ans += cnt;
        }
        return ans;
    }
}

C++ Code
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class Solution {
public:
    long long zeroFilledSubarray(vector<int>& nums) {
        long long ans = 0;
        int cnt = 0;
        for (int& v : nums) {
            cnt = v ? 0 : cnt + 1;
            ans += cnt;
        }
        return ans;
    }
};

Go Code
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func zeroFilledSubarray(nums []int) (ans int64) {
	cnt := 0
	for _, v := range nums {
		if v != 0 {
			cnt = 0
		} else {
			cnt++
		}
		ans += int64(cnt)
	}
	return
}

TypeScript Code
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function zeroFilledSubarray(nums: number[]): number {
    let ans = 0;
    let cnt = 0;
    for (const v of nums) {
        cnt = v ? 0 : cnt + 1;
        ans += cnt;
    }
    return ans;
}