Patching Array
<p>Given a sorted integer array <code>nums</code> and an integer <code>n</code>, add/patch elements to the array such that any number in the range <code>[1, n]</code> inclusive can be formed by the sum of some elements in the array.</p>

<p>Return <em>the minimum number of patches required</em>.</p>

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

<pre>
<strong>Input:</strong> nums = [1,3], n = 6
<strong>Output:</strong> 1
Explanation:
Combinations of nums are [1], [3], [1,3], which form possible sums of: 1, 3, 4.
Now if we add/patch 2 to nums, the combinations are: [1], [2], [3], [1,3], [2,3], [1,2,3].
Possible sums are 1, 2, 3, 4, 5, 6, which now covers the range [1, 6].
So we only need 1 patch.
</pre>

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

<pre>
<strong>Input:</strong> nums = [1,5,10], n = 20
<strong>Output:</strong> 2
Explanation: The two patches can be [2, 4].
</pre>

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

<pre>
<strong>Input:</strong> nums = [1,2,2], n = 5
<strong>Output:</strong> 0
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 1000</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>4</sup></code></li>
	<li><code>nums</code> is sorted in <strong>ascending order</strong>.</li>
	<li><code>1 &lt;= n &lt;= 2<sup>31</sup> - 1</code></li>
</ul>
Greedy; Array
class Solution:
    def minPatches(self, nums: List[int], n: int) -> int:
        x = 1
        ans = i = 0
        while x <= n:
            if i < len(nums) and nums[i] <= x:
                x += nums[i]
                i += 1
            else:
                ans += 1
                x <<= 1
        return ans
