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
func queensAttacktheKing(queens [][]int, king []int) (ans [][]int) {
	n := 8
	s := [8][8]bool{}
	for _, q := range queens {
		s[q[0]][q[1]] = true
	}
	for a := -1; a <= 1; a++ {
		for b := -1; b <= 1; b++ {
			if a != 0 || b != 0 {
				x, y := king[0]+a, king[1]+b
				for 0 <= x && x < n && 0 <= y && y < n {
					if s[x][y] {
						ans = append(ans, []int{x, y})
						break
					}
					x += a
					y += b
				}
			}
		}
	}
	return
}