1248. Count Number of Nice Subarrays

https://leetcode.com/problems/count-number-of-nice-subarrays

Description

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:

• 1 <= nums.length <= 50000

• 1 <= nums[i] <= 10^5

• 1 <= k <= nums.length

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