0632. Smallest Range Covering Elements from K Lists

https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists

Description

You have k lists of sorted integers in non-decreasing order. Find the smallest range that includes at least one number from each of the k lists.

We define the range [a, b] is smaller than range [c, d] if b - a < d - c or a < c if b - a == d - c.

Example 1:

**Input:** nums = [[4,10,15,24,26],[0,9,12,20],[5,18,22,30]]
**Output:** [20,24]
**Explanation:** 
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].

Example 2:

**Input:** nums = [[1,2,3],[1,2,3],[1,2,3]]
**Output:** [1,1]

Example 3:

**Input:** nums = [[10,10],[11,11]]
**Output:** [10,11]

Example 4:

**Input:** nums = [[10],[11]]
**Output:** [10,11]

Example 5:

**Input:** nums = [[1],[2],[3],[4],[5],[6],[7]]
**Output:** [1,7]

Constraints:

• nums.length == k

• 1 <= k <= 3500

• 1 <= nums[i].length <= 50

• -105 <= nums[i][j] <= 105

• nums[i] is sorted in non-decreasing order.

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