Closest Subsequence Sum
<p>You are given an integer array <code>nums</code> and an integer <code>goal</code>.</p>

<p>You want to choose a subsequence of <code>nums</code> such that the sum of its elements is the closest possible to <code>goal</code>. That is, if the sum of the subsequence&#39;s elements is <code>sum</code>, then you want to <strong>minimize the absolute difference</strong> <code>abs(sum - goal)</code>.</p>

<p>Return <em>the <strong>minimum</strong> possible value of</em> <code>abs(sum - goal)</code>.</p>

<p>Note that a subsequence of an array is an array formed by removing some elements <strong>(possibly all or none)</strong> of the original array.</p>

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

<pre>
<strong>Input:</strong> nums = [5,-7,3,5], goal = 6
<strong>Output:</strong> 0
<strong>Explanation:</strong> Choose the whole array as a subsequence, with a sum of 6.
This is equal to the goal, so the absolute difference is 0.
</pre>

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

<pre>
<strong>Input:</strong> nums = [7,-9,15,-2], goal = -5
<strong>Output:</strong> 1
<strong>Explanation:</strong> Choose the subsequence [7,-9,-2], with a sum of -4.
The absolute difference is abs(-4 - (-5)) = abs(1) = 1, which is the minimum.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3], goal = -7
<strong>Output:</strong> 7
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 40</code></li>
	<li><code>-10<sup>7</sup> &lt;= nums[i] &lt;= 10<sup>7</sup></code></li>
	<li><code>-10<sup>9</sup> &lt;= goal &lt;= 10<sup>9</sup></code></li>
</ul>
Bit Manipulation; Array; Two Pointers; Dynamic Programming; Bitmask; Sorting
class Solution:
    def minAbsDifference(self, nums: List[int], goal: int) -> int:
        n = len(nums)
        left = set()
        right = set()

        self.getSubSeqSum(0, 0, nums[: n // 2], left)
        self.getSubSeqSum(0, 0, nums[n // 2 :], right)

        result = inf
        right = sorted(right)
        rl = len(right)

        for l in left:
            remaining = goal - l
            idx = bisect_left(right, remaining)

            if idx < rl:
                result = min(result, abs(remaining - right[idx]))

            if idx > 0:
                result = min(result, abs(remaining - right[idx - 1]))

        return result

    def getSubSeqSum(self, i: int, curr: int, arr: List[int], result: Set[int]):
        if i == len(arr):
            result.add(curr)
            return

        self.getSubSeqSum(i + 1, curr, arr, result)
        self.getSubSeqSum(i + 1, curr + arr[i], arr, result)
