Longest Common Prefix
<p>Write a function to find the longest common prefix string amongst an array of strings.</p>

<p>If there is no common prefix, return an empty string <code>&quot;&quot;</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> strs = [&quot;flower&quot;,&quot;flow&quot;,&quot;flight&quot;]
<strong>Output:</strong> &quot;fl&quot;
</pre>

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

<pre>
<strong>Input:</strong> strs = [&quot;dog&quot;,&quot;racecar&quot;,&quot;car&quot;]
<strong>Output:</strong> &quot;&quot;
<strong>Explanation:</strong> There is no common prefix among the input strings.
</pre>

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

<ul>
	<li><code>1 &lt;= strs.length &lt;= 200</code></li>
	<li><code>0 &lt;= strs[i].length &lt;= 200</code></li>
	<li><code>strs[i]</code> consists of only lowercase English letters if it is non-empty.</li>
</ul>
Trie; Array; String
class Solution {
    /**
     * @param String[] $strs
     * @return String
     */
    function longestCommonPrefix($strs) {
        $rs = '';
        for ($i = 0; $i < strlen($strs[0]); $i++) {
            for ($j = 1; $j < count($strs); $j++) {
                if ($strs[0][$i] != $strs[$j][$i]) {
                    return $rs;
                }
            }
            $rs = $rs . $strs[0][$i];
        }
        return $rs;
    }
}
