LeetCode-in-Java

2348. Number of Zero-Filled Subarrays

Medium

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:

Solution

public class Solution {
    public long zeroFilledSubarray(int[] nums) {
        long cnt = 0L;
        long local = 0L;
        for (int n : nums) {
            if (n == 0) {
                cnt += ++local;
            } else {
                local = 0;
            }
        }
        return cnt;
    }
}