Queens That Can Attack the King
<p>On a <strong>0-indexed</strong> <code>8 x 8</code> chessboard, there can be multiple black queens and one white king.</p>

<p>You are given a 2D integer array <code>queens</code> where <code>queens[i] = [xQueen<sub>i</sub>, yQueen<sub>i</sub>]</code> represents the position of the <code>i<sup>th</sup></code> black queen on the chessboard. You are also given an integer array <code>king</code> of length <code>2</code> where <code>king = [xKing, yKing]</code> represents the position of the white king.</p>

<p>Return <em>the coordinates of the black queens that can directly attack the king</em>. You may return the answer in <strong>any order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1200-1299/1222.Queens%20That%20Can%20Attack%20the%20King/images/chess1.jpg" style="width: 400px; height: 400px;" />
<pre>
<strong>Input:</strong> queens = [[0,1],[1,0],[4,0],[0,4],[3,3],[2,4]], king = [0,0]
<strong>Output:</strong> [[0,1],[1,0],[3,3]]
<strong>Explanation:</strong> The diagram above shows the three queens that can directly attack the king and the three queens that cannot attack the king (i.e., marked with red dashes).
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1200-1299/1222.Queens%20That%20Can%20Attack%20the%20King/images/chess2.jpg" style="width: 400px; height: 400px;" />
<pre>
<strong>Input:</strong> queens = [[0,0],[1,1],[2,2],[3,4],[3,5],[4,4],[4,5]], king = [3,3]
<strong>Output:</strong> [[2,2],[3,4],[4,4]]
<strong>Explanation:</strong> The diagram above shows the three queens that can directly attack the king and the three queens that cannot attack the king (i.e., marked with red dashes).
</pre>

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

<ul>
	<li><code>1 &lt;= queens.length &lt; 64</code></li>
	<li><code>queens[i].length == king.length == 2</code></li>
	<li><code>0 &lt;= xQueen<sub>i</sub>, yQueen<sub>i</sub>, xKing, yKing &lt; 8</code></li>
	<li>All the given positions are <strong>unique</strong>.</li>
</ul>
Array; Matrix; Simulation
function queensAttacktheKing(queens: number[][], king: number[]): number[][] {
    const n = 8;
    const s: boolean[][] = Array.from({ length: n }, () => Array.from({ length: n }, () => false));
    queens.forEach(([x, y]) => (s[x][y] = true));
    const ans: number[][] = [];
    for (let a = -1; a <= 1; ++a) {
        for (let b = -1; b <= 1; ++b) {
            if (a || b) {
                let [x, y] = [king[0] + a, king[1] + b];
                while (x >= 0 && x < n && y >= 0 && y < n) {
                    if (s[x][y]) {
                        ans.push([x, y]);
                        break;
                    }
                    x += a;
                    y += b;
                }
            }
        }
    }
    return ans;
}
