Minimum Operations to Make a Uni-Value Grid
<p>You are given a 2D integer <code>grid</code> of size <code>m x n</code> and an integer <code>x</code>. In one operation, you can <strong>add</strong> <code>x</code> to or <strong>subtract</strong> <code>x</code> from any element in the <code>grid</code>.</p>

<p>A <strong>uni-value grid</strong> is a grid where all the elements of it are equal.</p>

<p>Return <em>the <strong>minimum</strong> number of operations to make the grid <strong>uni-value</strong></em>. If it is not possible, return <code>-1</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/2000-2099/2033.Minimum%20Operations%20to%20Make%20a%20Uni-Value%20Grid/images/gridtxt.png" style="width: 164px; height: 165px;" />
<pre>
<strong>Input:</strong> grid = [[2,4],[6,8]], x = 2
<strong>Output:</strong> 4
<strong>Explanation:</strong> We can make every element equal to 4 by doing the following: 
- Add x to 2 once.
- Subtract x from 6 once.
- Subtract x from 8 twice.
A total of 4 operations were used.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/2000-2099/2033.Minimum%20Operations%20to%20Make%20a%20Uni-Value%20Grid/images/gridtxt-1.png" style="width: 164px; height: 165px;" />
<pre>
<strong>Input:</strong> grid = [[1,5],[2,3]], x = 1
<strong>Output:</strong> 5
<strong>Explanation:</strong> We can make every element equal to 3.
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/2000-2099/2033.Minimum%20Operations%20to%20Make%20a%20Uni-Value%20Grid/images/gridtxt-2.png" style="width: 164px; height: 165px;" />
<pre>
<strong>Input:</strong> grid = [[1,2],[3,4]], x = 2
<strong>Output:</strong> -1
<strong>Explanation:</strong> It is impossible to make every element equal.
</pre>

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

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= m * n &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= x, grid[i][j] &lt;= 10<sup>4</sup></code></li>
</ul>
Array; Math; Matrix; Sorting
function minOperations(grid, x) {
    const arr = grid.flat(2);
    arr.sort((a, b) => a - b);
    const median = arr[Math.floor(arr.length / 2)];

    let res = 0;
    for (const val of arr) {
        const c = Math.abs(val - median) / x;
        if (c !== (c | 0)) return -1;
        res += c;
    }

    return res;
}
