<p>You are given a binary array <code>nums</code>.</p>

<p>A subarray of an array is <strong>good</strong> if it contains <strong>exactly</strong> <strong>one</strong> element with the value <code>1</code>.</p>

<p>Return <em>an integer denoting the number of ways to split the array </em><code>nums</code><em> into <strong>good</strong> subarrays</em>. As the number may be too large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>

<p>A subarray is a contiguous <strong>non-empty</strong> sequence of elements within an array.</p>

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

<pre>
<strong>Input:</strong> nums = [0,1,0,0,1]
<strong>Output:</strong> 3
<strong>Explanation:</strong> There are 3 ways to split nums into good subarrays:
- [0,1] [0,0,1]
- [0,1,0] [0,1]
- [0,1,0,0] [1]
</pre>

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

<pre>
<strong>Input:</strong> nums = [0,1,0]
<strong>Output:</strong> 1
<strong>Explanation:</strong> There is 1 way to split nums into good subarrays:
- [0,1,0]
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>0 &lt;= nums[i] &lt;= 1</code></li>
</ul>

class Solution:
    def numberOfGoodSubarraySplits(self, nums: List[int]) -> int:
        pre=0
        ans=1
        d=defaultdict(int)
        d={0:1}
        flag=False
        mod=10**9+7
        for i in nums:
            pre+=i
            x=pre-1
            if i==1 and x in d:
                if flag:
                    ans*=d[x]%mod
                else:
                    ans+=0
                flag=True
            d[pre]=d.get(pre,0)+1
        if 1 not in nums:
            return 0
        return ans%mod

25500