<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 isPossible(string &s1,string &s2,string s){
        if(s.length()==0)return true;
        int i=0;
        while(i<s1.length()){
            string temp = s1.substr(i,s.length());
            if(temp!=s)return false;
            i=i+s.length();
        }

        if(i>s1.length())return false;

        i=0;

        while(i<s2.length()){
            string temp = s2.substr(i,s.length());
            if(temp!=s)return false;
            i=i+s.length();
        }

        if(i>s2.length())return false;

        return true;
    }
    string method1(string &s1,string &s2){
        string small = s1;
        string large =s2;
        if(s2.length()<s1.length()){
            small=s2;
            large = s1;
        }

        string ans = "";
        string temp_ans = "";
        int i=0;
        while(1){
            if(isPossible(small,large,temp_ans)){
                ans=temp_ans;
            }
            if(i>=small.length())break;
            temp_ans+=small[i];
            i++;
        }

        return ans;

    }
    string gcdOfStrings(string str1, string str2) {
        return method1(str1,str2);
    }
};
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