Count Subarrays Containing Exactly k Odd Values

### Problem Return the number of nonempty contiguous subarrays of nums containing exactly k odd elements. Even elements may appear anywhere within those intervals. ```cpp class Solution { public: int numberOfSubarrays(vector<int>& nums, int k); }; ``` ### Examples **Example 1:** ```text Input: nums = [2,1,2,1,2], k = 2 Output: 4 Explanation: A valid interval starts at0 or1 and ends at3 or4, giving2*2 choices. ``` **Example 2:** ```text Input: nums = [1,2,1], k = 1 Output: 4 Explanation: The intervals are[1] at either end,[1,2],and[2,1]. ``` ### Constraints - There are 1 to 50000 elements. - Each nums value is an integer in `[1,100000]`. - `1 <= k <= nums.length`. ### Contract considerations The source has positive input values, but only their odd/even status matters. ```hint Read the boundary condition Does a subarray with more than k odd elements count, and may even elements remain inside a counted interval? ``` ### Boundary reminders The source has positive input values, but only their odd/even status matters.