The distance of a pair of integers `a` and `b` is defined as the absolute difference between `a` and `b`.

Given an integer array `nums` and an integer `k`, return the `kth` smallest distance among all the pairs `nums[i]` and `nums[j]` where `0 <= i < j < nums.length`.

Example 1:

    Input: nums = [1,3,1], k = 1
    Output: 0
    Explanation: Here are all the pairs:
    (1,3) -> 2
    (1,1) -> 0
    (3,1) -> 2
    Then the 1st smallest distance pair is (1,1), and its distance is 0.

Example 2:

    Input: nums = [1,1,1], k = 2
    Output: 0

Example 3:

    Input: nums = [1,6,1], k = 3
    Output: 5

Constraints:

- `n == nums.length`
- `2 <= n <= 104`
- `0 <= nums[i] <= 106`
- `1 <= k <= n * (n - 1) / 2`