Strobogrammatic Number II
<p>Given an integer <code>n</code>, return all the <strong>strobogrammatic numbers</strong> that are of length <code>n</code>. You may return the answer in <strong>any order</strong>.</p>

<p>A <strong>strobogrammatic number</strong> is a number that looks the same when rotated <code>180</code> degrees (looked at upside down).</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> n = 2
<strong>Output:</strong> ["11","69","88","96"]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> n = 1
<strong>Output:</strong> ["0","1","8"]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 14</code></li>
</ul>
Recursion; Array; String
func findStrobogrammatic(n int) []string {
	var dfs func(int) []string
	dfs = func(u int) []string {
		if u == 0 {
			return []string{""}
		}
		if u == 1 {
			return []string{"0", "1", "8"}
		}
		var ans []string
		pairs := [][]string{{"1", "1"}, {"8", "8"}, {"6", "9"}, {"9", "6"}}
		for _, v := range dfs(u - 2) {
			for _, p := range pairs {
				ans = append(ans, p[0]+v+p[1])
			}
			if u != n {
				ans = append(ans, "0"+v+"0")
			}
		}
		return ans
	}
	return dfs(n)
}