Number of Zero-Filled Subarrays
Problem Statement - link #
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.
Examples #
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 <= 10^5-10^9 <= nums[i] <= 10^9
Solutions #
class Solution {
public:
long long zeroFilledSubarray(vector<int>& nums) {
long long res = 0;
long long cur = 0;
for(int &i: nums) {
if(i == 0) {
cur++;
}
else {
res += (cur * (cur + 1)) / 2;
cur = 0;
}
}
if(cur != 0) {
res += (cur * (cur + 1)) / 2;
}
return res;
}
};