1248. Count Number of Nice Subarrays

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Problem

Given an array of integers nums and an integer k. A continuous subarray is called nice if there are k odd numbers on it.

Return **the number of *nice* sub-arrays**.

  Example 1:

Input: nums = [1,1,2,1,1], k = 3
Output: 2
Explanation: The only sub-arrays with 3 odd numbers are [1,1,2,1] and [1,2,1,1].

Example 2:

Input: nums = [2,4,6], k = 1
Output: 0
Explanation: There is no odd numbers in the array.

Example 3:

Input: nums = [2,2,2,1,2,2,1,2,2,2], k = 2
Output: 16

  Constraints:

Solution (Java)

class Solution {
    public int numberOfSubarrays(int[] nums, int k) {
        int oddLen = 0;
        int startIndex = 0;
        int num = 0;
        int endIndex;
        int res = 0;
        boolean hasK;
        for (int i = 0; i < nums.length; i++) {
            hasK = false;
            endIndex = i;
            if (nums[i] % 2 == 1) {
                oddLen++;
            }
            while (oddLen >= k) {
                hasK = true;
                if (nums[startIndex++] % 2 == 1) {
                    oddLen--;
                }
                num++;
            }
            res += num;
            while (hasK && ++endIndex < nums.length && nums[endIndex] % 2 == 0) {
                res += num;
            }
            num = 0;
        }
        return res;
    }
}

Explain:

nope.

Complexity: