<p>Given a string <code>s</code>, partition <code>s</code> such that every <span data-keyword="substring-nonempty">substring</span> of the partition is a <span data-keyword="palindrome-string"><strong>palindrome</strong></span>. Return <em>all possible palindrome partitioning of </em><code>s</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> s = "aab"
<strong>Output:</strong> [["a","a","b"],["aa","b"]]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> s = "a"
<strong>Output:</strong> [["a"]]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 16</code></li>
	<li><code>s</code> contains only lowercase English letters.</li>
</ul>

class Solution {
public:
    bool check(string t)
    {
        int l = 0, r = t.size()-1;
        while(l<r)
            if(t[l++]!=t[r--])
                return false;
        return true;
    }

    void part(string s, string t, vector<string> &v, set<vector<string>> &ans, int i, int n, int cnt)
    {
        if(i==n)
        {
            if(cnt==n)
                ans.insert(v);
            return;
        }
        t += s[i];
        if(check(t))
        {
            v.push_back(t);
            cnt += t.size();
            part(s, "", v, ans, i+1, n, cnt);
            cnt -= t.size();
            v.pop_back();
        }
        part(s, t, v, ans, i+1, n, cnt);
    }

    vector<vector<string>> partition(string s) {
        int n = s.size();
        vector<string> v;
        set<vector<string>> ans;
        string t = "";
        part(s, t, v, ans, 0, n, 0);
        return vector<vector<string>> (ans.begin(), ans.end());
    }
};
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