<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:
    bool isdivide(string s,string t){
        
        if(t.size()%s.size()!=0)return false;
       int k=t.size()/s.size();
        string temp="";
        for(int i=0;i<k;i++){
            temp+=s;
        }
        if(temp==t)return true;
        return false;
        
    }
    string gcdOfStrings(string str1, string str2) {
        
        int n=str1.size();
        int m=str2.size();
        if(str1.size()<str2.size()){
           while(n>0){
            string str=str1.substr(0,n);
            if(isdivide(str,str1) && isdivide(str,str2)){
                return str;
            }
            n--;
           }
        }
        
       else{
           while(m>0){
               string str=str2.substr(0,m);
               if(isdivide(str,str1) && isdivide(str,str2)){
                   return str;
               }
               m--;
           }
       }
        return "";
        
    }
};
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