<p>For two strings <code>s</code> and <code>t</code>, we say &quot;<code>t</code> divides <code>s</code>&quot; if and only if <code>s = t + t + t + ... + t + t</code> (i.e., <code>t</code> is concatenated with itself one or more times).</p>

<p>Given two strings <code>str1</code> and <code>str2</code>, return <em>the largest string </em><code>x</code><em> such that </em><code>x</code><em> divides both </em><code>str1</code><em> and </em><code>str2</code>.</p>

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

<pre>
<strong>Input:</strong> str1 = &quot;ABCABC&quot;, str2 = &quot;ABC&quot;
<strong>Output:</strong> &quot;ABC&quot;
</pre>

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

<pre>
<strong>Input:</strong> str1 = &quot;ABABAB&quot;, str2 = &quot;ABAB&quot;
<strong>Output:</strong> &quot;AB&quot;
</pre>

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

<pre>
<strong>Input:</strong> str1 = &quot;LEET&quot;, str2 = &quot;CODE&quot;
<strong>Output:</strong> &quot;&quot;
</pre>

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

<ul>
	<li><code>1 &lt;= str1.length, str2.length &lt;= 1000</code></li>
	<li><code>str1</code> and <code>str2</code> consist of English uppercase letters.</li>
</ul>

class Solution {
public:
    string another_method(string a, string b)
    {
        while (true)
        {
            if (a[0] != b[0]) return "";
            bool flag2 = true;
            int i;
            for (i = 0; i < a.size(); i += b.size())
            {
                if (a.substr(i, b.size()) != b) flag2 = false;
            }
            if (a.size() != i) flag2 = false;
            if (flag2)
            {
                return b;
            }
            b.pop_back();
        }
    }
    string gcdOfStrings(string str1, string str2) {
        string a = str1;
        string res = another_method(a, str2);
        a = str2;
        string second_res = another_method(a, res);
        while (second_res != res)
        {
            a == str2 ? a = str1 : a = str2;
            res = another_method(a, second_res);
            a == str2 ? a = str1 : a = str2;
            second_res = another_method(a, res);
        }

        return res;
    }
};

30536