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
class Solution {
    public List<List<Integer>> shiftGrid(int[][] grid, int k) {
        int m = grid.length, n = grid[0].length;
        List<List<Integer>> ans = new ArrayList<>();
        for (int i = 0; i < m; ++i) {
            List<Integer> row = new ArrayList<>();
            for (int j = 0; j < n; ++j) {
                row.add(0);
            }
            ans.add(row);
        }
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                int idx = (i * n + j + k) % (m * n);
                int x = idx / n, y = idx % n;
                ans.get(x).set(y, grid[i][j]);
            }
        }
        return ans;
    }
}