<p>You have <code>k</code> lists of sorted integers in <strong>non-decreasing&nbsp;order</strong>. Find the <b>smallest</b> range that includes at least one number from each of the <code>k</code> lists.</p>

<p>We define the range <code>[a, b]</code> is smaller than range <code>[c, d]</code> if <code>b - a &lt; d - c</code> <strong>or</strong> <code>a &lt; c</code> if <code>b - a == d - c</code>.</p>

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

<pre>
<strong>Input:</strong> nums = [[4,10,15,24,26],[0,9,12,20],[5,18,22,30]]
<strong>Output:</strong> [20,24]
<strong>Explanation: </strong>
List 1: [4, 10, 15, 24,26], 24 is in range [20,24].
List 2: [0, 9, 12, 20], 20 is in range [20,24].
List 3: [5, 18, 22, 30], 22 is in range [20,24].
</pre>

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

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

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

<ul>
	<li><code>nums.length == k</code></li>
	<li><code>1 &lt;= k &lt;= 3500</code></li>
	<li><code>1 &lt;= nums[i].length &lt;= 50</code></li>
	<li><code>-10<sup>5</sup> &lt;= nums[i][j] &lt;= 10<sup>5</sup></code></li>
	<li><code>nums[i]</code>&nbsp;is sorted in <strong>non-decreasing</strong> order.</li>
</ul>

class Solution:
    def smallestRange(self, nums: List[List[int]]) -> List[int]:
        all_nums = []
        for i, row in enumerate(nums):
            for num in row:
                all_nums.append((num, i))
        all_nums.sort()

        row_target = len(nums)
        row_count = 0
        row_counter = collections.Counter()

        q = collections.deque()
        res = [float('-inf'), float('inf')]
        for num, row_i in all_nums:
            q.append((num, row_i))
            row_counter[row_i] += 1
            if row_counter[row_i] == 1:
                row_count += 1
            
            while row_count == row_target:
                new_start = q[0][0]
                new_end = q[-1][0]

                if new_end - new_start < res[1] - res[0]:
                    res = [new_start, new_end]
                
                _, removed_i = q.popleft()
                row_counter[removed_i] -= 1
                if row_counter[removed_i] == 0:
                    row_count -= 1
        
        return res
24000