3Sum Closest
<p>Given an integer array <code>nums</code> of length <code>n</code> and an integer <code>target</code>, find three integers in <code>nums</code> such that the sum is closest to <code>target</code>.</p>

<p>Return <em>the sum of the three integers</em>.</p>

<p>You may assume that each input would have exactly one solution.</p>

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

<pre>
<strong>Input:</strong> nums = [-1,2,1,-4], target = 1
<strong>Output:</strong> 2
<strong>Explanation:</strong> The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
</pre>

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

<pre>
<strong>Input:</strong> nums = [0,0,0], target = 1
<strong>Output:</strong> 0
<strong>Explanation:</strong> The sum that is closest to the target is 0. (0 + 0 + 0 = 0).
</pre>

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

<ul>
	<li><code>3 &lt;= nums.length &lt;= 500</code></li>
	<li><code>-1000 &lt;= nums[i] &lt;= 1000</code></li>
	<li><code>-10<sup>4</sup> &lt;= target &lt;= 10<sup>4</sup></code></li>
</ul>
Array; Two Pointers; Sorting
/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
var threeSumClosest = function (nums, target) {
    nums.sort((a, b) => a - b);
    let ans = 1 << 30;
    const n = nums.length;
    for (let i = 0; i < n; ++i) {
        let j = i + 1;
        let k = n - 1;
        while (j < k) {
            const t = nums[i] + nums[j] + nums[k];
            if (t === target) {
                return t;
            }
            if (Math.abs(t - target) < Math.abs(ans - target)) {
                ans = t;
            }
            if (t > target) {
                --k;
            } else {
                ++j;
            }
        }
    }
    return ans;
};
