<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]:
        d = defaultdict(list)
        for i, evs in enumerate(nums):
            for v in evs:
                d[v].append(i)
        keys = sorted(d.keys())
        lo = 0
        n = len(nums)
        dd = defaultdict(int)
        le, ri = -1, float('Inf')
        have = 0
        for hi in range(len(keys)):
            for x in d[keys[hi]]:
                dd[x] += 1
                if dd[x] == 1:
                    have += 1
            while have == n:
                curr = keys[hi] - keys[lo]
                if ri - le > curr:
                    ri = keys[hi]
                    le = keys[lo]
                for x in d[keys[lo]]:
                    dd[x] -= 1
                    if dd[x] == 0:
                        have -= 1
                lo += 1
        return [le, ri]
23300