Given a binary array nums and an integer goal, return the number of non-empty subarrays with a sum equal to goal.
A subarray is a contiguous part of the array.
Example 1:
Input: nums = [1,0,1,0,1], goal = 2
Output: 4
Explanation: The 4 subarrays with sum equal to 2 are: [1,0,1], [1,0,1,0], [0,1,0,1], [1,0,1].
Example 2:
Input: nums = [0,0,0,0,0], goal = 0
Output: 15
Explanation: Every non-empty subarray sums to 0, and there are 15 subarrays total (5 choose 2 + 5 = 15).
Example 3:
Input: nums = [1,1,1], goal = 2
Output: 2
Explanation: The 2 subarrays with sum equal to 2 are: [1,1] (indices 0-1) and [1,1] (indices 1-2).
1 <= nums.length <= 3 * 10^4nums[i] is either 0 or 10 <= goal <= nums.length