Find K Closest Elements
<p>Given a <strong>sorted</strong> integer array <code>arr</code>, two integers <code>k</code> and <code>x</code>, return the <code>k</code> closest integers to <code>x</code> in the array. The result should also be sorted in ascending order.</p>

<p>An integer <code>a</code> is closer to <code>x</code> than an integer <code>b</code> if:</p>

<ul>
	<li><code>|a - x| &lt; |b - x|</code>, or</li>
	<li><code>|a - x| == |b - x|</code> and <code>a &lt; b</code></li>
</ul>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">arr = [1,2,3,4,5], k = 4, x = 3</span></p>

<p><strong>Output:</strong> <span class="example-io">[1,2,3,4]</span></p>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">arr = [1,1,2,3,4,5], k = 4, x = -1</span></p>

<p><strong>Output:</strong> <span class="example-io">[1,1,2,3]</span></p>
</div>

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

<ul>
	<li><code>1 &lt;= k &lt;= arr.length</code></li>
	<li><code>1 &lt;= arr.length &lt;= 10<sup>4</sup></code></li>
	<li><code>arr</code> is sorted in <strong>ascending</strong> order.</li>
	<li><code>-10<sup>4</sup> &lt;= arr[i], x &lt;= 10<sup>4</sup></code></li>
</ul>
Array; Two Pointers; Binary Search; Sorting; Sliding Window; Heap (Priority Queue)
int target;

class Solution {
public:
    static bool cmp(int& a, int& b) {
        int v = abs(a - target) - abs(b - target);
        return v == 0 ? a < b : v < 0;
    }

    vector<int> findClosestElements(vector<int>& arr, int k, int x) {
        target = x;
        sort(arr.begin(), arr.end(), cmp);
        vector<int> ans(arr.begin(), arr.begin() + k);
        sort(ans.begin(), ans.end());
        return ans;
    }
};