<p>Given a binary array <code>nums</code> and an integer <code>goal</code>, return <em>the number of non-empty <strong>subarrays</strong> with a sum</em> <code>goal</code>.</p>

<p>A <strong>subarray</strong> is a contiguous part of the array.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,0,1,0,1], goal = 2
<strong>Output:</strong> 4
<strong>Explanation:</strong> The 4 subarrays are bolded and underlined below:
[<u><strong>1,0,1</strong></u>,0,1]
[<u><strong>1,0,1,0</strong></u>,1]
[1,<u><strong>0,1,0,1</strong></u>]
[1,0,<u><strong>1,0,1</strong></u>]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [0,0,0,0,0], goal = 0
<strong>Output:</strong> 15
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 3 * 10<sup>4</sup></code></li>
	<li><code>nums[i]</code> is either <code>0</code> or <code>1</code>.</li>
	<li><code>0 &lt;= goal &lt;= nums.length</code></li>
</ul>

class Solution:
    def numSubarraysWithSum(self, nums: List[int], goal: int) -> int:
        left = 0

        total = 0
        res = 0
        queue = []
        last_one = -1
        
        if goal == 0:
            count = 0
            for i in range(len(nums)):
                if nums[i] == 0:
                    count += 1
                else:
                    res += (count + 1) * count // 2
                    count = 0
            res += (count + 1) * count // 2
            return res
        for r in range(len(nums)):
            cur = nums[r]

            if cur == 1:
                total += 1
                queue.append(r)
            
            if total > goal:
                left = queue.pop(0)
                last_one = left
                left += 1
                total -= 1
            if total == goal:
                res += queue[0] - last_one
        return res

        
17700