<p>The <strong>distance of a pair</strong> of integers <code>a</code> and <code>b</code> is defined as the absolute difference between <code>a</code> and <code>b</code>.</p> <p>Given an integer array <code>nums</code> and an integer <code>k</code>, return <em>the</em> <code>k<sup>th</sup></code> <em>smallest <strong>distance among all the pairs</strong></em> <code>nums[i]</code> <em>and</em> <code>nums[j]</code> <em>where</em> <code>0 <= i < j < nums.length</code>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> nums = [1,3,1], k = 1 <strong>Output:</strong> 0 <strong>Explanation:</strong> Here are all the pairs: (1,3) -> 2 (1,1) -> 0 (3,1) -> 2 Then the 1<sup>st</sup> smallest distance pair is (1,1), and its distance is 0. </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> nums = [1,1,1], k = 2 <strong>Output:</strong> 0 </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> nums = [1,6,1], k = 3 <strong>Output:</strong> 5 </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == nums.length</code></li> <li><code>2 <= n <= 10<sup>4</sup></code></li> <li><code>0 <= nums[i] <= 10<sup>6</sup></code></li> <li><code>1 <= k <= n * (n - 1) / 2</code></li> </ul>