<p>Given a string <code>s</code>, check if it can be constructed by taking a substring of it and appending multiple copies of the substring together.</p>

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

<pre>
<strong>Input:</strong> s = &quot;abab&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> It is the substring &quot;ab&quot; twice.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;aba&quot;
<strong>Output:</strong> false
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;abcabcabcabc&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> It is the substring &quot;abc&quot; four times or the substring &quot;abcabc&quot; twice.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>4</sup></code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
</ul>

class Solution {
public:
    
    vector<string> f(string s, int length){
        vector<string>ans;
        for(int i=0; i<s.length()-length+1; i+=length){
            ans.push_back(s.substr(i, length));
        }
        return ans;
    }
    
    bool check(vector<string> s){
        set<string>s1;
        for(string t:s){
            s1.insert(t);
            if(s1.size()>1) return false;
        }
        return true;
    }
    
    bool repeatedSubstringPattern(string s) {
        int n=s.length();
        for(int i=1; i<=n/2; i++){
            if(n%i==0){
                if(check(f(s,i))==true) return true;
            }
        }
        
        return false;
    }
    
};
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