2023-03-21 Daily Challenge

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In: DailyChallenge

Today I have done leetcode's March LeetCoding Challenge with cpp.

March LeetCoding Challenge 21

Description

Number of Zero-Filled Subarrays

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

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  long long zeroFilledSubarray(vector<int>& nums) {
    int count = 0;
    long long answer = 0;
    for(auto i : nums) {
      count += !i;
      if(i && count) {
        answer += 1LL * count * (count + 1) / 2;
        count = 0;
      }
    }
    answer += 1LL * count * (count + 1) / 2;
    return answer;
  }
};

// Accepted
// 48/48 cases passed (134 ms)
// Your runtime beats 98.49 % of cpp submissions
// Your memory usage beats 99.55 % of cpp submissions (106.4 MB)
Algorithm