Shift 2D Grid
<p>Given a 2D <code>grid</code> of size <code>m x n</code>&nbsp;and an integer <code>k</code>. You need to shift the <code>grid</code>&nbsp;<code>k</code> times.</p>

<p>In one shift operation:</p>

<ul>
	<li>Element at <code>grid[i][j]</code> moves to <code>grid[i][j + 1]</code>.</li>
	<li>Element at <code>grid[i][n - 1]</code> moves to <code>grid[i + 1][0]</code>.</li>
	<li>Element at <code>grid[m&nbsp;- 1][n - 1]</code> moves to <code>grid[0][0]</code>.</li>
</ul>

<p>Return the <em>2D grid</em> after applying shift operation <code>k</code> times.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1200-1299/1260.Shift%202D%20Grid/images/e1.png" style="width: 400px; height: 178px;" />
<pre>
<strong>Input:</strong> <code>grid</code> = [[1,2,3],[4,5,6],[7,8,9]], k = 1
<strong>Output:</strong> [[9,1,2],[3,4,5],[6,7,8]]
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1200-1299/1260.Shift%202D%20Grid/images/e2.png" style="width: 400px; height: 166px;" />
<pre>
<strong>Input:</strong> <code>grid</code> = [[3,8,1,9],[19,7,2,5],[4,6,11,10],[12,0,21,13]], k = 4
<strong>Output:</strong> [[12,0,21,13],[3,8,1,9],[19,7,2,5],[4,6,11,10]]
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> <code>grid</code> = [[1,2,3],[4,5,6],[7,8,9]], k = 9
<strong>Output:</strong> [[1,2,3],[4,5,6],[7,8,9]]
</pre>

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

<ul>
	<li><code>m ==&nbsp;grid.length</code></li>
	<li><code>n ==&nbsp;grid[i].length</code></li>
	<li><code>1 &lt;= m &lt;= 50</code></li>
	<li><code>1 &lt;= n &lt;= 50</code></li>
	<li><code>-1000 &lt;= grid[i][j] &lt;= 1000</code></li>
	<li><code>0 &lt;= k &lt;= 100</code></li>
</ul>
Array; Matrix; Simulation
func shiftGrid(grid [][]int, k int) [][]int {
	m, n := len(grid), len(grid[0])
	ans := make([][]int, m)
	for i := range ans {
		ans[i] = make([]int, n)
	}
	for i := 0; i < m; i++ {
		for j := 0; j < n; j++ {
			idx := (i*n + j + k) % (m * n)
			x, y := idx/n, idx%n
			ans[x][y] = grid[i][j]
		}
	}
	return ans
}