Problem Statement

Given a binary called nums and an integer called goal, return the number of subarrays that have a sum equal to goal.

A subarray is a part of the array that is continuous, meaning all its elements are next to each other.

Examples

Example 1

• Input: nums = [1, 1, 0, 1, 1], goal = 2
• Expected Output: 5
• Justification: The subarrays with a sum of 2 are: [1, 1] (from index 0 to 1), [1, 1, 0] (from index 0 to 2), [1, 0, 1] (from index 1 to 3), [0, 1, 1] (from index 2 to 5), and [1, 1] (from index 4 to 5).

Example 2

• Input: nums = [1, 1, 1, 1, 0, 0], goal = 3
• Expected Output: 4
• Justification: The subarrays with a sum of 3 are: [1, 1, 1] (from index 0 to 2), [1, 1, 1] (from index 1 to 3), [1, 1, 1, 0] (from index 1 to 4), and [1, 1, 1, 0, 0] (from index 1 to 5).

Example 3

• Input: nums = [0, 0, 0, 0, 1, 0, 1], goal = 1
• Expected Output: 12
• Justification: The subarrays with a sum of 1 are: [0, 0, 0, 0, 1], [0, 0, 0, 1], [0, 0, 1], [0, 1], [1], [0, 0, 0, 0, 1, 0], [0, 0, 0, 1, 0], [0, 0, 1, 0], [0, 1, 0], [1, 0], [0, 1], and [1]`.

Constraints:

• 1 <= nums.length <= 3 * 10⁴
• nums[i] is either 0 or 1.
• 0 <= goal <= nums.length

Try it yourself

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