<p>Given an integer array <code>nums</code> and two integers <code>lower</code> and <code>upper</code>, return <em>the number of range sums that lie in</em> <code>[lower, upper]</code> <em>inclusive</em>.</p>

<p>Range sum <code>S(i, j)</code> is defined as the sum of the elements in <code>nums</code> between indices <code>i</code> and <code>j</code> inclusive, where <code>i &lt;= j</code>.</p>

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

<pre>
<strong>Input:</strong> nums = [-2,5,-1], lower = -2, upper = 2
<strong>Output:</strong> 3
<strong>Explanation:</strong> The three ranges are: [0,0], [2,2], and [0,2] and their respective sums are: -2, -1, 2.
</pre>

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

<pre>
<strong>Input:</strong> nums = [0], lower = 0, upper = 0
<strong>Output:</strong> 1
</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>-2<sup>31</sup> &lt;= nums[i] &lt;= 2<sup>31</sup> - 1</code></li>
	<li><code>-10<sup>5</sup> &lt;= lower &lt;= upper &lt;= 10<sup>5</sup></code></li>
	<li>The answer is <strong>guaranteed</strong> to fit in a <strong>32-bit</strong> integer.</li>
</ul>

class Solution:
    def countRangeSum(self, nums: List[int], lower: int, upper: int) -> int:
        # Divide and Conquer
        n = len(nums)
        if n <= 1:
            # Doesn't actually have to convert to int, but for clarity
            return int(nums and lower <= nums[0] <= upper)
        else:
            mid = n // 2

            # Suffix sum of the left array
            suffix = [0] * (mid + 1)
            for i in range(mid - 1, -1, -1):
                suffix[i] = suffix[i + 1] + nums[i]

            # We exclude index mid from suffix
            suffix = suffix[:-1]

            # Prefix sum of the right array
            prefix = [0] * (n - mid + 1)
            for i in range(mid, n):
                prefix[i - mid + 1] = prefix[i - mid] + nums[i]

            # Again, we exclude index mid from prefix
            # We also want to sort prefix, excluding mid
            prefix = sorted(prefix[1:])

            # Find count when start index is on the left array, and right index is on the right array
            count = 0
            for suf in suffix:
                count += bisect.bisect_right(prefix, upper - suf) - bisect.bisect_left(prefix, lower - suf)

            return count + self.countRangeSum(nums[:mid], lower, upper) + self.countRangeSum(nums[mid:], lower, upper)
35036