2348.Number of Zero-Filled Subarrays

tags: `Medium`,`Array`,`Math`

題目描述

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.

範例

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

解答

C++












class Solution {
public:
    long long zeroFilledSubarray(vector<int>& nums) {
        long long ans = 0, count = 0;
        for (auto num : nums) {
            if (num) count = 0;
            else count++;
            ans += count;
        }
        return ans;
    }
};

Yen-Chi ChenTue, Mar 21, 2023

Python










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

Yen-Chi ChenTue, Mar 21, 2023

Javascript














function zeroFilledSubarray(nums) {
  let countZero = 0;
  let result = 0;
  for (const num of nums) {
    if (num === 0) {
      countZero++;
    } else {
      countZero = 0;
    }
    result += countZero;
  }

  return result;
}

MarsgoatTue, Mar 21, 2023

Reference

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