<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:
        # Handle trivial cases
        if sum(nums) == 0:
            return 0
        elif sum(nums) == 1:
            return 1

        start_idx = nums.index(1) 
        end_idx = 0
        for i in reversed(range(len(nums))):
            if nums[i]:
                end_idx = i
                break

        n_splits = 1    # The total number of possible splits
        n_zeros = 1     # The number of zeros in-between two ones
        for i in range(start_idx, end_idx + 1):
            if nums[i]:
                if n_zeros > 1:
                    n_splits *= n_zeros
                n_zeros = 0
            n_zeros += 1
        
        return n_splits % 1000000007
1801