<p>Given an integer array <code>nums</code> and an integer <code>k</code>, return <em>the length of the shortest non-empty <strong>subarray</strong> of </em><code>nums</code><em> with a sum of at least </em><code>k</code>. If there is no such <strong>subarray</strong>, return <code>-1</code>.</p>

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

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> nums = [1], k = 1
<strong>Output:</strong> 1
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> nums = [1,2], k = 4
<strong>Output:</strong> -1
</pre><p><strong class="example">Example 3:</strong></p>
<pre><strong>Input:</strong> nums = [2,-1,2], k = 3
<strong>Output:</strong> 3
</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>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li>
</ul>

class Solution:
    def shortestSubarray(self, nums: List[int], k: int) -> int:
        cums = [0]
        for i, num in enumerate(nums):
            cums.append(num + cums[-1])
        min_length = math.inf
        stack_val = []
        stack_idx = []
        for i in range(len(cums)):
            while stack_val and cums[i] <= stack_val[-1]:
                stack_val.pop()
                stack_idx.pop()
            
            if stack_val:
                low, high = 0, len(stack_val)-1
                while low < high - 1:
                    mid = int((low + high) // 2)
                    if cums[i] - stack_val[mid] >= k:
                        low = mid
                    else:
                        high = mid
                if cums[i] - stack_val[high] >= k:
                    min_length = min(min_length, i - stack_idx[high])
                elif cums[i] - stack_val[low] >= k:
                    min_length = min(min_length, i - stack_idx[low])
                
            stack_val.append(cums[i])
            stack_idx.append(i)

        return -1 if min_length == math.inf else min_length

32000