Strobogrammatic Number
<p>Given a string <code>num</code> which represents an integer, return <code>true</code> <em>if</em> <code>num</code> <em>is a <strong>strobogrammatic number</strong></em>.</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> num = &quot;69&quot;
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> num = &quot;88&quot;
<strong>Output:</strong> true
</pre>

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

<pre>
<strong>Input:</strong> num = &quot;962&quot;
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>1 &lt;= num.length &lt;= 50</code></li>
	<li><code>num</code> consists of only digits.</li>
	<li><code>num</code> does not contain any leading zeros except for zero itself.</li>
</ul>
Hash Table; Two Pointers; String
func isStrobogrammatic(num string) bool {
	d := []int{0, 1, -1, -1, -1, -1, 9, -1, 8, 6}
	for i, j := 0, len(num)-1; i <= j; i, j = i+1, j-1 {
		a, b := int(num[i]-'0'), int(num[j]-'0')
		if d[a] != b {
			return false
		}
	}
	return true
}